Cortisol, a steroid hormone your adrenal glands produce, has widespread and varied effects throughout your body. It plays roles in stress management, exercise and inflammation. Your cortisol levels rise and fall in response to these conditions. Cortisol can inhibit the immune system, suppressing inflammation. Its anti-inflammatory effects make cortisol a useful drug in conditions where inflammation needs to be controlled, such as forms of arthritis and autoimmune conditions.
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Exercise Effects
Cortisol's main purpose during exercise is to raise your blood sugar level to make glucose available to parts of the body, such as your heart, lungs and muscles, where it is needed most. To accomplish this, cortisol inhibits insulin secretion, promotes the breakdown of proteins and fats throughout the body and stimulates the liver to use these compounds to manufacture glucose. To balance its blood sugar-raising effect, cortisol stimulates the liver to produce glycogen, the short-term storage form of glucose. Concurrent with cortisol release, a part of your brain known as the hypothalamus releases a hormone called vasopressin, which causes the kidneys to retain water, thereby increasing blood pressure. As part of the cortisol response, in moderate exercise your brain releases the neurotransmitter dopamine, which heightens your motivation and enjoyment of your exercise.
Longer sessions of exercise, such as increased sets in weight training, or endurance activities, such as jogging, may increase cortisol levels more than brief sessions of exercise. A study published in the May 2012 issue of the "Journal of Strength and Conditioning Research" found that high-intensity exercise causes greater elevations of cortisol than moderate-intensity exercise. High-intensity exercise may also result in overtraining, a condition characterized by decreased performance, fatigue and constant soreness. In the study, trained men and women performed high-intensity bouts of weight training. Results showed considerably higher cortisol values than for more typical strength training routines. Researchers recommend gradual implementation of high-intensity exercise to avoid injury and setbacks in reaching training goals.
Moderate exercise may be useful for reducing stress-related depression, which is associated with elevated cortisol levels, concludes a study published in the April 2012 issue of the "International Journal of Sports Medicine." In the laboratory study of rats, a 10-week swimming program resulted in increased levels of serotonin, noradrenaline and dopamine, brain neurotransmitters that are all decreased in depression.
Reference
http://dujs.dartmouth.edu/fall-2010/the-physiology-of-stress-cortisol-and-the-hypothalamic-pituitary-adrenal-axis#.VAKwYiyCOK0
http://books.google.com/books?id=01TsP_7pUZ0C&pg=PA298&dq=longterm+effects+of+elevated+cortisol+levels&hl=en&sa=X&ei=Q8ThT7TUL4Xi0gHD-53BAw&ved=0CDwQ6AEwAA#v=onepage&q=longterm%20effects%20of%20elevated%20cortisol%20levels&f=true
Top 10 Reasons Exercise Is Bad For You
Text by Ben Greenfield
There are people who need to exercise, and who absolutely benefit from exercise.
Exercise has rescued obese individuals from a sedentary lifestyle, saved men and women from being ravaged by cardiovascular disease, and allowed for athletes to train their body to perform above and beyond normal capacity.
But exercise also has a dark side – dangerous disadvantages that affect thousands of people each day, and those disadvantages can be summed up in these top 10 reasons exercise is bad for you.
10. Exercise is addictive.
Consistent exercise causes the body to produce endorphins, which are hormones secreted by your pituitary gland to block pain, decrease anxiety and create feelings of euphoric happiness. But endorphins are chemically similar to the drug morphine, and so for many people, compulsive exercise
can be psychologically addictive. For regular exercisers, and especially for bodybuilders, triathletes, cyclists or marathoners, reducing or stopping exercise suddenly – or even missing one single workout – can result in depression, stress and anxiety.
This "mouse on a wheel" attraction to exercise can result in overtraining, missing family obligations and social gatherings because of an intense "need" to exercise, and a worry that fitness will be lost or weight will gain with a day of missed exercise. The pursuit of exercise turns from a way to experience the beauty of nature or spend time with friends to a feeling of going to work or being stuck in a rut.
The Fix: Include at least one day per week in which you do not exercise or your exercise involves no structure (such as playing a new sport). Unless you are paid for your physical performance, if your exercise ever begins to feel like a job, then switch to something new and fresh. Finally, engage in alternate ways to satisfy your brain, including cooking, wine tasting, music, new books, social events, and sex. If you do find yourself addicted to exercise, consider cognitive behavioral therapy, neurofeedback, and in severe cases, pharmaceutical interventions to break the addiction. Exercise addiction is not worth destroying your body and relationships.
9. Exercise Hurts The Heart
In one study, British researchers examined 12 runners and rowers with an average age of 57, who each had completed a total of 43 years of consistent training and 178 marathons, 65 ultramarathons, and 4 Ironman triathlons. Half of the athletes showed signs of fibrosis, or scarring of heart tissue, compared to none of age-matched "non-exercising" controls.
In addition, wear and tear of years of heavy-duty workouts or lifelong endurance exercise can weaken heart muscles – predisposing you to a condition called "ventricular arrhythmia" in which the heart beats
erratically. This is probably due to damage to the right chamber of the heart, which can disrupt normal heart rate and rhythm, and this has literally put an end to the career of several pro endurance athletes, who engage in the type of training necessary for this problem to occur.
The Fix: Avoid excessive exercise, especially a combination of high intensity and high volume workouts. If you do find yourself in this situation, such as during the build-up to an Ironman triathlon, then engage in good warm-ups and proper cool-downs after each workout, and include at least one total recovery day. As much as possible, try to avoid competing in events such as an Ironman triathlon or ultra-marathon more than once per year.
8. Exercise is associated with body perception disorders.
Body dysmorphic disorder is a psychological disorder in which you are excessively concerned about a perceived defect in your physical features, such as your arm or leg muscles being to small or your waistline not being thin enough. This can result in heavy, often socially isolated exercise to "repair the defect".
Typically, this type of activity can begin in adolescence or early adulthood, but can stay with you your entire life as you strive to achieve or maintain the "perfect body". You may turn to bodybuilding, marathoning, cycling or any other activity which uses the same muscles over and over again to try to hammer away at your perceived defects, even when it comes to the detriment of your joints or health. If you don’t have the time to exercise and address what you perceive to be a significant body issue, this
can result in depression, social anxiety, and even social phobia, or complete avoidance of being in public, especially where your body might be exposed.
Often, you might justify your behavior by believing that you are a serious athlete who can never work too hard or too long at your sport, and this can often lead to excessive and addictive exercise in an attempt to control or lose weight, or sometimes to gain muscle or "sculpt" a body part.
The Fix: Learn to accept yourself for who you are, and understand that you are your own worst critic. Unless you’re an actor or a model, most other people really don’t care what your body looks like, so there’s no reason to be embarrassed. Striving for a perfect body is an uphill battle that will always result in failure at some point, probably when you’re 60, 70 or 80. There’s nothing wrong with looking good, but don’t become obsessed about it unless your income depends on it.
7. Exercise can break up families.
In 2010, The Wall Street Journal published the article "A Workout Ate My Marriage" describing how couples become increasingly conflicted as a spouse becomes obsessed with a particular exercise goal, such as extreme weight loss or an Ironman triathlon – to the detriment of time spent with family.
Often, since the exercise goal can be justified as "noble", it is difficult for a spouse or family member to negotiate with the over-exerciser to spend more time with family.
The Fix: If your goals require you to exercise "excessively", then at least attempt to include family in exercise. Join a gym with free childcare so you and the spouse can exercise together, get a jogging stroller and bicycle trailer, and train indoors with the kids at home so a spouse can go enjoy free time.
6. Exercise can cause diabetes.
In my book "Holistic Fueling For Ironman Triathletes" I discuss the propensity for endurance athletes to spend lots of time at coffeeshops and bakeries, engaging in daily chronic consumption of scones,
big "healthy" muffins, baked goodies, bagels and artisan breads. Later in the evening, post "long training day", they’re back to pastas, lasagnas, spaghettis, pizzas, and more carbohydrate laden foods. And in between these meals is a constant, steady intake of sugar packed energy bars, energy gels,
energy drinks and energy chews.
Not only do these constantly surging blood sugar levels cause sugar addiction and damage to blood vessels and nerves, but they vastly increase risk for Type II diabetes as the cell surface receptors for insulin eventually become less and less sensitive to elevated insulin levels attempting to shove all the extra sugar into the muscles.
The Fix: Break the sugar addiction. Go two weeks on a low carbohydrate diet, even if it means that exercise levels are decreased. If you’re addicted to exercise, changing to a lower carbohydrate intake can be near to impossible, so often, you must FIRST break the exercise addiction and then break the
sugar addiction. This may require something as dramatic as an extended vacation to a place where A) you only have access to healthy food and B) do not have your bike, your gym, your swimsuit and goggles, and your running shoes.
5. Exercise destroys diets.
Whether you are trying to eat a diet lower in inflammatory compounds to manage an autoimmune disease or cancer, trying to eat a lower calorie diet to lose weight or teach your body to eat less, or trying to switch to a low carbohydrate diet as mentioned earlier, it is very hard to accomplish these
nutritional changes while you are engaged in heavy exercise patterns.
This is often what causes people to stop healthy lifestyle changes: they get excited about changing their daily routine, eating better, and exercising more, but heavy exercise volume causes food cravings that make it impossible to adjust to a healthy diet, the individual becomes discouraged, and simply quits altogether.
The Fix: In my"REV Diet" book, the first phase (Reboot) involves precise instructions for reducing calories and detoxifying the body, but a key component of that phase is limited exercise significantly while the body learns to burn more fats, use less sugar as a fuel, and become accustomed to the dietary changes. One very good substitute for exercise during this time is yoga, which doesn’t burn a significant number of calories, and can be done without derailing the diet.
4. Exercise causes inflammation.
Endurance exercise can increase oxygen utilization to over 10 to 20 times the resting state, and all this extra oxygen consumption then increases production of free radicals, which are produced as the oxygen is used to convert energy into ATP for muscle contractions. This enhanced free radical generation causes oxidative damage to muscles and other tissues, and although regular physical exercise can build the antioxidant free radical defense system, intense and high volume exercise can overwhelm these defenses and cause significant free radical damage.
Oxidative stress from free radicals damages cellular proteins, membranes and genes and leads to a state of chronic, systemic inflammation. Chronic inflammation is implicated in diseases such as cancer, heart disease, strokes, MS, Alzheimer¹s, Parkinson¹s, premature aging and almost any debilitating, degenerative condition you can name.
The Fix: You can certainly put a band-aid over the problem by consuming a full spectrum antioxidant, but you can only eat so many berries, nuts and dark leafy greens before your stomach gets full. Eventually, you must give your body a break from free radical damage and simply stop exercising so
much. Since endurance, aerobic exercise is the biggest culprit for free radical damage, try to limit this type of training. Even in an Ironman build-up, I personally avoid doing anything more than 1 long bike, 1 long swim and 1 long run each week – and everything else is short intense bursts or high intensity interval training, which you can read about in my article"Why You’re Wasting Your Time With Long, Slow Aerobic Workouts" which explains why interval exercise can cause lower blood sugar, increased hormonal response to exercise, lower insulin levels and increased fat burning with much, much less time spent exercising.
3. Exercise is stressful.
The adrenal glands are two thumb-sized glands sitting atop your kidneys. They produce hormones like norepinephrine, cortisol and DHEA, which allow your body to respond and make adjustments to physical or emotional stress. If the intensity and frequency of the stres becomes too great, then
the adrenal glands can begin to become exhausted, and the hormones that they produce can become depleted, resulting in serious imbalances that can cause issue like estrogen dominance in women or testosterone deficiencies in men.
The end result is a tired, chronically fatigued individual who has disrupted sleep, low libido, worn-out looking eyes, a set and stressed jawline, and a "skinny fat" body look no matter how much exercise they do. Sound familiar? I just described 90% of the marathoners and Ironman triathletes out there.
The Fix: In addition to incorporating the other fixes I’ve described such as lowering exercise and enhancing focus on recovery, you can pull yourself out of adrenal exhaustion with complete rest and recovery, avoiding caffeine and central nervous system stimulants, and also by incorporating stress-fighting and cortisol-stabilizing compounds like maca root powder and phosphatidylserine supplements.
2. Exercise damages the joints.
I was playing on the trail with my boys yesterday and a man ran by with a scowl across his face. Perhaps his sour disposition was due to the knee brace on his right leg, the exercise strap above his left IT band, and the compression sleeve on his elbow. Despite his body falling to pieces, he was limping along the trail, trying to push his body through a run. Since exercise is addictive, you’ll often see endurance athletes trying to push through and continue their chronic repetitive motion training no matter
what, often to the continued detriment and breakdown of the body’s worn and tired joints.
I worked with a sports medicine physician for 3 years, and most endurance athletes that came in were trying to figure out how they could still do their marathon or triathlon even though they had plantar fasciitis, IT band friction syndrome, or shoulder tendonitis. They’d be miserable during their
event, but would still do it. While you can certainly be "patched together" with braces, bands, sleeves, and cortisol shots to complete your event, you can end up taking years off your joints.
If you like the idea of knee replacements, hip replacements, and not being able to play in the backyard with your grandkids without teeth-gritting pain then strap on that brace and head outside to run through the pain. Otherwise, just stop.
The Fix: Run on a wide variety of running surfaces and terrains, and avoid only exercising in one plane of motion (running, cycling and swimming are typically only "front-to-back" activities). Instead, choose side-to-side motions like tennis, basketball or soccer, and attempt to address a wide range of musculature with your exercise patterns. Know when to identify whether you’re just pushing through pain because you simply must exercise, and find something else to do, like read a book.
1. Exercise causes premature aging.
In 4 Easy Ways To Ensure Your Skin Doesn¹t Look Like A Wrinkled Elephant From Your Outdoor Exercise Habits I describe how to make sure your outdoor, sunny exercise doesn’t end up giving you a face like a prune. But excessively wrinkled skin, which is vastly accelerated by the free radical damage mentioned earlier in this article, is not the only reason that people who exercise too much look worn and aged.
The heart has a finite number of beats, the back has a finite number of bends, and the cartilage has a finite number of shock absorptions, and once you’ve reached your quota, your body begins to fail. Combined with a fibrotic heart, worn adrenal glands, and chronic, systemic inflammation, you have the perfect storm for a prematurely aged and broken down body.
The Fix: In my interview with Arthur de Vany we discuss why an exercise program of sprint
interval training and brief, heavy bouts of weight training is probably better for the aging individual. When this type of protocol is combined with very limited amounts of steady endurance exercise, goals like Ironman triathlon or marathoning can still be completed without excessive body aging.
So those are the top 10 reasons why exercise is bad for you. Please don’t misinterpret me, because I believe that a lifetime of healthy physical activity is one of the best things you can do for your body and your brain.
But a lifetime of indiscriminate, chronic repetitive motion exercise like a rat on a wheel is entirely another matter, and you ought to seriously reconsider your priorities if you are stuck in that rut.
Are you concerned that you may be exercising too much? Or do you think this is all blown way out of proportion? Feel free to leave your comments, questions and feedback at www.bengreenfieldfitness.com
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Running – Heading out the door Lessons from watching an Ironman Warming Up in Training
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Lactic acid build-up has been blamed for producing muscle pain, but three culprits—lactate, certain acids, and adenosine triphosphate (ATP)—are actually at fault. These substances are released during muscle contraction, causing pain and discomfort, scientists at the University of Utah found.
In the study, researchers isolated the substances and injected them into mouse nerve cells. There was no response initially, but when all three substances were injected at the same time, a many of the nerve cells responded. The neurons responded differently depending on how much of the substances were injected.
The results were similar in human subjects, who experienced little reaction when injected with the substances separately in their thumbs, but reported pain, swelling, and fatigue once the chemicals were combined. The accumulation of these substances is likely what causes your muscles to hit a wall, so to speak, when you exercise too much.
Which is better? Well, it all depends…
For building fat-scorching lean muscle mass to help you drop the pounds and tone up, a new study in the Journal of Applied Physiology trumped the long-time believed theory that training with heavy weights for 6-12 repetitions promotes the most muscle growth. Over a 10-week period, one group lifted heavy weights for 8-12 reps for 3 sets while the other group lifted three sets of light weights for 25-30 repetitions. The study found “both the heavy and light groups saw significant gains in muscle volume — as measured by MRI — with no difference among the groups.” However, the group that lifted heavier did gain more strength. Therefore, if you’re lifting weights not only to look good naked, but also to increase your strength for everyday activities and sports – as well as to increase bone density – than it may be a good idea to progress to heavier weights.
Lifting heavy weights does not necessarily build the huge bulky muscles some women fear. The bottom line is women don’t have the hormonal makeup to build a masculine physique because females lack the sufficient amounts of the hormone testosterone that help men pack on more lean muscle mass. But lifting heavy weights does help increase bone density and prevent osteoporosis. Strength training helps your bones retain calcium, a key mineral for bone health, and lifting weights “promotes a healthy mechanical stress in the skeletal system,” which increases bone density. Since heavier weights add more stress, they can be a more efficient way to increase bone density and prevent osteoporosis.
The downside to heavier weights, though, is the more significant stress they place on your joints. If you have nagging aches and pains, the light weight, high-rep scheme may be your best bet, at least until you build muscular strength, increase endurance, and your joint pain diminishes. Lifting light weights may also be more ideal if you’re an endurance athlete. The heavier the weight, the more stress it places on your muscles, causing more microfiber damage and a longer necessary recovery period. If you’re training for a marathon and you’re incorporating strength training into your routine as a way to help prevent injury and fix muscle imbalances, then light weights, which promote muscle endurance and limit microscopic muscle damage, may be best. Likewise, if you’re training for a power event like the 100m sprint, powerlifting exercises of 4-6 reps may better suit your needs leading up to race season.
However, if your sole reasons for being in the weight room are to lose weight, tone up, and look good naked, then a variety can be your best option. If you’re lifting 3 days a week, incorporate a heavy weight day, a moderate weight day, and a light weight day. Your body needs a variety of exercises and training variables to lose excess flab and tone up. Vary weight intensity and rep scheme to build both strength and endurance by keeping your muscles guessing. No matter what, the key to results is to overload your muscles and lift until failure, and to progress accordingly. Work towards advancing in weight for your heavy lifting and increasing reps and/or weight on your light days.
Why not look super sleek and sexy all dolled up in your designer clothes and look even better when you ditch them?
Personally, I prefer lifting heavy for 4-6 sets of 6-12 reps. Traditional lifts like squats, deadlifts, pull-ups, and bench press should not be ignored as they will help build muscle, burn fat, and create a shapely physique.
My 18-year-old son and I are going to start working out together. He wants to add mass. Is it better to use low reps and heavy weight, or to use moderate weight with increased reps? My son wants to max out all the time, but I’m concerned he’s going to hurt himself.
A: As a former IFBB professional bodybuilder, this is the question I get asked most often at the gym. Many people would look at me funny when I used light-to-moderate weights because I looked like I could handle a lot more. But in my early days, I found out the hard way that training seriously heavy too much can cause elbow and shoulder injuries.
Contrary to popular belief, you can build thick, dense muscle tissue with moderate weights and high reps just as much as training with max poundage. And with lighter weights, there’s less chance of injury.
Science backs this up. In a recent study conducted at the University of Ontario, researchers took two groups of men and compared the cellular response for muscle growth and recovery using either light-to-moderate weights with high volume (15–20-rep range), or lifting heavy weights with less volume (6–10-rep range). Researchers found that whether the men lifted with 30% of their maximum weight until muscles were completely exhausted, or 80% of their maximum until their arms and/or legs were exhausted, both groups developed very similar cellular changes related to muscle growth, meaning that both routines produced similar results. But, according to researchers, lifting the lighter weights built more muscular endurance than lifting with fewer reps and heavier weights. Also, the greater work volume in the light-to-moderate group resulted in more calories burned, leaving them in better overall physical condition than the heavy lifters.
The key to determining just how much you and your son should be lifting is gauging your point of personal muscle failure. To become stronger, gain lean muscle and get in peak physical condition, you need to lift weights until your muscles are exhausted. If you are using a lighter-weight approach, fatigue should set in after 15–20 reps. In this case, based on the study, if you can’t push yourself to lift the weight at least 15 reps, then it’s too heavy; if you can lift it more than 20 times, then the weights are too light. Through my own personal experience, I believe this to be true, and found that pushing my rep range between 10 and 18 is the best target number.
Another important aspect is to keep your ego out of it. Don’t worry about what other lifters think about the amount you can lift. The integrity of the rep is much more important than the amount of weight lifted.
[ Creatine vs. Nitric Oxide ]
Probably the most important thing to remember is that when it comes to cortisol and food intake, is that when glycogen (stored carbohydrates) are too low, cortisol is going to go up. When you think about it, this makes perfect sense. Carbohydrates are the body’s number one source of energy, so when this source is really low, the body has to begin to pull fuel from other sources (the only other two sources are protein and fats). These rising cortisol levels will stimulate the breakdown of these precious proteins and lean tissue into individual amino acids (building blocks of muscle) to be converted into glucose (carbohydrate). The rising levels will also stimulate the breakdown of fatty acids in the fat stores, making more body fat available to be used as fuel. In order to prevent this from happening, athletes need to keep their glycogen stores as full as possible and make carbohydrates the bulk of your food intake.
When it comes to exercise duration, more is not always better. Training too much and too frequent can actually cause strength and gain losses due to the elevated cortisol. Listening to the body and following the basic principles of weight training and make your diet spot on will ensure that you do not overdo it because too much of a good thing isn’t always the best for you.
Optimal training time has been debated over and over again. The time and intensity of the exercise will also determine the amount of cortisol released. Even if you exercise at a low intensity for upwards of 60 mins, the body’s glycogen stores will decrease significantly and increase the stress put on the body, thus increasing the cortisol released. The more training you do, the better your body will get at dealing with the added stress and decrease the need for cortisol release. For weightlifters, the optimal time to spend in the gym should be about 45 mins per session. It is definitely possible to exercise 5-6 days per week, depended upon if you rest and recover properly, eat right, do not train the same muscle group on consecutive days, and most importantly sleep!
The vast majority of men and women in the United States are constantly worried about not getting enough exercise. Working out is hard to fit into a busy schedule, particularly when free time is at a premium.
Though exercise is an important part of a healthy lifestyle, it is also important to avoid overdoing the work out routine. For most adults, exercising between 30 and 45 minutes a day is enough to gain the benefits of exercise without changing the benefits to extreme fatigue. Start one of WeightTraining.com's FREE workout plans and start becoming fit today!
Overtraining
It is quite common for fitness newcomers to fall prey to overtraining – a condition in which your body at best hits a plateau and at worst enters a full-blown catabolic state.
Catabolism is a breaking down within living organisms of complex tissues into simpler tissues, and it happens as a result of a negative nitrogen balance in the body. For anyone who is trying to burn fat and increase lean muscle mass, the situation is one which should be avoided at all costs. Unfortunately, many gym-goers are completely oblivious to the concept of catabolism and what it does to the body.
This destructive catabolic state occurs primarily due to the hormone cortisol. This steroidal hormone is naturally released by the adrenal gland during states of high physical and mental stress. While it is a completely normal function of the body, excess cortisol release can have a drastic negative impact on the body. It can lead to the weakening of joints and osteoporosis as well as fat increase in the abdominal region. Cortisol primarily harms the body in three ways:
Breaking Down Tissues and Canceling Potential Growth
Converting Protein to Glucose
Reducing the Body's Protein Synthesis Abilities
The most common cause of excess cortisol release in physically active individuals is lack of rest. Strength training and intense aerobic activity also leads to microscopic tearing in the muscle fibers, and the muscles cannot heal and grow without proper rest. This is a major pitfall in the world of bodybuilding, particularly for amateurs who are new to the endeavor and want to spend hours upon hours in the gym. With studies showing that excess cortisol levels are released in the body even after only an hour of exercise, it is important to limit your sessions to no longer than 45 minutes.
Excess cortisol isn't the only negative symptom of working out longer than 45 minutes. There are various other side effects that come with overdoing it in the gym, one of which is the increased risk of injury. For heavy weight lifters this tends to manifest itself through joint problems such as tendinitis and dislocations. These overuse conditions can be avoided by utilizing proper technique and keeping one's workout sessions to 45 minutes or less.
Overtraining has negative implications beyond just those associated with the body. Workout enthusiasts who overdo it in the gym are more prone to suffering from irritability, anxiety and depression. This comes back to the release of excess cortisol in the body, creating an unhealthy hormone imbalance. These negative repercussions are more likely to go unnoticed as they can be much more subtle than their physical counterparts.
If the mental and physiological shortcomings aren't bad enough, there is another troubling symptom of overtraining: the weakening of the immune system. Studies have shown that overtraining can cause rapidly decreased levels of antibodies in one's system, leaving one increasingly susceptible to illnesses. Since one can't work out when he or she is sick, this can be extremely detrimental to the level of progress that one wishes to attain through exercise.
Benefits of Moderate Exercise
Moderate exercise is working out between 30 and 45 minutes a day. This is the best range for any type of exercise, regardless of whether it is cardiovascular or weight training. Numerous benefits result from moderate exercise which include:
Lower Risk of Developing Numerous Health Conditions: Conditions that are helped with this amount of exercise include diabetes, high cholesterol, high blood pressure and cancer risks associated with obesity.
Lower Body Weight: Exercising regularly will naturally result in a higher metabolism and better fat burning potential in the body. This causes a lower body weight.
Decreased Stress Hormones in the Body: The stress hormone cortisol is reduced and rebalanced after exercising. This helps reduce overall stress and helps the body relax.
Better Sleep: Insomnia is a problem of the past when regular exercise is part of a daily routine.
Increased energy: Cardiovascular exercise in particular results in increases in energy levels. This means getting through the day is no longer a chore.
Reduction of Boredom: It is difficult to remain bored while exercising, particularly if working out with a friend.
Downfall of Too Much Exercise
While it might seem odd to think that it is possible to get too much exercise, it is possible to overstress and overwork the muscles. Exercise fatigue is a common problem among those who work out too long.
In general, it is better to avoid over exercising because too much of a good thing can have negative effects. The common negative effects associated with too much exercise include:
Insomnia: While an appropriate amount of exercise makes it easier to sleep, too much has the opposite effect. It will make sleep a challenge.
High Stress Levels: Over exercising results in cortisol production after the muscles begin to become fatigued. The goal of exercise is lowering the stress hormone, but too much results in an increased production of the hormone instead.
High Injury Risks: Tired muscles that are over stressed can risk injuries during and after the exercise is complete.
Weakened Immune System: After a certain point, too much exercise results in a lower resistance to sicknesses.
Improving Health With Exercise
We all know that health is improved with exercise, the key is avoiding the point of over exercising that leads to muscle fatigue and ultimately health problems. Determining where to set a balance is a necessary part of maintaining great health and the perfect beach body. Understanding the factors that relate to improving health with exercise is the first step in creating a cut-off point.
One major factor is the mindset behind exercise. Difficult goals make the motivation to exercise greatly reduced while simple goals are easier to keep up with. Exercise should not become a chore and should not be a necessary part of the day. Instead, it should be something enjoyable while working it around a busy schedule as it fits in.
Another key component is current physical fitness level. An athlete who has worked up stamina will be able to spend more time exercising while someone who is just starting out will want to begin slowly and work up to 30 or 45 minutes a day. Those who are just beginning should begin with only a few minutes at a time and gradually increase over time as it becomes easier.
Current health is another factor to consider when determining an appropriate amount. Any individual who has diabetes, high blood pressure or similar conditions should discuss exercise with their doctor beforehand to avoid overworking the body. This is particularly true of heart related problems since exercise causes the heart to work faster.
The final factor in determining a good amount of exercise is personal stamina. Stamina in exercise takes time to build up and is a large factor in determining a good length of time when just starting out. Even those who have excellent stamina should keep exercise to around 45 minutes at a time to avoid overworking the muscles.
Getting the Most Out of Exercise
Since it is not necessary to work out for hours every day, an in fact it is better to limit exercise to moderate amounts to avoid over exercising and causing problems with the muscles, it is then a matter of getting the most out of the 30 to 45 minute time period.
Depending on individual goals for exercise, the best results will require different forms of exercise or routines. This means that if the goal is building up muscle or gaining strength, the exercise plan and routine will differ from a goal of losing weight and slimming down.
Final Thoughts
Regardless of the specific goal, most individuals will have the best results when combining aerobic exercise with weight training.
Weight training builds up the muscle, allowing the body to form more muscle mass and thus effectively burn more calories throughout the day. Aerobic exercise is high-intensity cardiovascular options that burn fat while strengthening the heart.
Anyone who has a goal of weight loss or losing excess fat should ensure that more days include cardiovascular exercise than weight training. With this goal, the ideal is having around four to five days of high intensity aerobic exercise and around two days of weight training to avoid the loss of muscle mass.
Those who are trying to build more muscle should opt for a slightly less cardiovascular intensive routine by cutting it back to three or four days with around three days of weight training.
Working out does not need to require excessive time periods. Instead, opt for a less time constraining routine that stops at 45 minutes. This will result in a healthy lifestyle without the fatigue of overworking. Don't forget to FOLLOW @WeightTraining for the latest fitness information!
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Periodical Exercise Therapeutics Update & Commentary: Exercise and Cortisol
Tagged: Cortisol
Resistance exercise overtraining and overreaching: neuroendocrine responses
Sports Med 823(2): 106, 1997.
Summary: Physiological effects of weight training are not nearly as well studied as those of aerobic exercise. This lengthy article reviews the neuroendocrine responses to weight training and overtraining. Only the section of the article dealing with cortisol will be summarized. For the purpose of this article the authors will be defining overtraining as an increase in number of repetitions or number of circuits or amount of weight lifted, leading to strength decrements. Often this decrease in performance is accompanied by generalized fatigue.
The direct stimulus for release of cortisol from the adrenal gland is ACTH (adrenocorticotropic hormone) from the anterior pituitary. ACTH is released due to CRH (corticotropin releasing hormone) from the hypothalamus. CRH is released regardless of the type of stress, i.e. physical, emotional. traumatic, etc. This cascade of hormonal responses to stress is known as the HPA axis (hypothalamic, pituitary, adrenal). Overtraining of any sort may lead to dysfunction of the HPA axis.
The release of cortisol in response to an exercise bout (moderate to high intensity for aerobic exercise and for all types of weight training bouts) is seen as beneficial. Cortisol is needed to help maintain blood glucose, while facilitating the metabolic shift towards greater fat oxidation.
Typically, the greater the amount of weight being lifted (i.e. greater stress), the higher the rise in cortisol during training. Moving to greater training volumes (more repetitions per exercise) or higher intensities (lifting greater weights) too quickly, may lead to higher resting cortisol levels. Yet when weight lifting is undertaken, cortisol levels may actually decline during the exercise bout.
Commentary: Cortisol is the classic "stress" hormone. Dr. Hans Selye, a pioneering stress physiologist, clearly established the essentiality of cortisol in allowing the body to withstand all types of stresses.(1) Selye found that if the adrenal glands were removed from animals they would quickly die, unable to deal with normal life stresses.
It would appear that some amount of cortisol is beneficial during a stress (e.g. weight training bout), while too much cortisol can become detrimental. When the volume of weight training is too great, it appears that even during rest, cortisol blood levels remain high. Cortisol can cause muscle tissue to break down thereby explaining why strength might actually start to decrease with higher levels of training (i.e. overtraining).
(1.) Selye H. The Stress of Life. New York: McGraw-Hill, 1956.
Effects of exercise on neuroendocrine secretions and glucose regulation at different times of day
Am J Physiol 274 (Endocrinol Metab 37):E1040, 1998.
Summary: A number of hormones exhibit diurnal variations, including cortisol. Typically, cortisol levels are highest in the early morning and lowest in the evening. These authors wanted to know if cortisol responses to exercise were dependent on the time of day in which exercise was undertaken. Twenty-two young men, in good physical condition, were recruited for the study. The men were divided into morning exercise group, late afternoon exercise group, and around midnight exercise group. Each exercise group underwent a 3-hr exercise session (at the designated time) which included moderate intensity, low intensity exercise and rest cycles on an arm/leg ergometer. Cortisol levels were measured at different time points throughout the three hour exercise session.
Only the group exercising during the late afternoon had a significant exercise-induced rise of cortisol. This is normally the time of day when cortisol levels would be decreasing.
Commentary: The most interesting aspect of this study is that the authors clearly demonstrated a different hormonal response to exercise which is influenced by the time of day in which exercise is undertaken. Most exercise studies tend to ignore diurnal variations and conduct their tests during the early morning hours. Interestingly, optimal sports performance tends to occur in the afternoon and early evening. This timing nicely corresponds to the greatest exercise-induced cortisol response as reported by these researchers.
Corticotrophic axis sensitivity after exercise in endurance-trained athletes
Clin Endocrinol 48:493, 1998.
Summary: Negative feedback from cortisol to the hypothalamus and pituitary is the normal way HPA axis regulation occurs. In animal studies repeated stress reduces the sensitivity of the HPA axis to negative feedback control. These authors used endurance-trained athletes as a model of repeated stress to test whether the HPA axis of humans also exhibits reduced feedback control.
Eight male marathon runners were asked to run for 2 hours after which a catheter was inserted into the arm vein. Blood could be collected for sampling and ACTH or CRH could be injected to assess the sensitivity of the runner's HPA axis. Saliva samples were also obtained to compare blood and salivary cortisol levels.
Cortisol levels remained elevated at least two hours after an intense and prolonged exercise bout. The results from the ACTH and CRH stimulation tests suggest that endurance athletes do have reduced pituitary feedback to hypercortisolism. This altered sensitivity may represent a beneficial adaptation in the HPA axis to endurance training.
Commentary: High levels of cortisol following an especially stressful exercise bout might facilitate recovery from that exercise bout. High cortisol can lead to feelings of euphoria and diminish pain sensations. It also has anti-inflammatory effects and may be helpful to blunt inflammatory responses following microtrauma to muscle and connective tissue.
These authors also clearly demonstrated that saliva cortisol changes correlate well with blood cortisol changes. This is an important confirmation of other studies which also found a good correlation. Furthermore, these authors actually found that salivary cortisol was a more accurate measure of cortisol during stimulation tests, when very high levels of cortisol occur. Salivary cortisol is an especially useful tool in the assessment of HPA axis function since saliva sampling is non-invasive and numerous samples can be easily obtained in an effort to account for the normal diurnal variation of saliva. The cortisol found in saliva actually represents the biologically active, unbound fraction of cortisol. This in fact may make salivary cortisol a more clinically relevant measure of HPA axis activity.
Metabolic effects of low cortisol during exercise in humans
J Appl Physiol 84(3): 939, 1998.
Summary: The metabolic effects of cortisol under resting conditions have been well established, as already mentioned in the first article's summary. The importance of cortisol during exercise has not been fully elucidated, although speculations abound. These authors wanted to determine some of the metabolic effects of exercise-induced cortisol in humans by blocking cortisol synthesis during an exercise bout.
Nine healthy college students were recruited for the study. All students underwent two bicycle ergometry tests. One was conducted the morning following an evening dose of placebo and the other was conducted following a dose of a cortisol blocking drug (metyrapone). Blood samples were taken throughout each exercise bout and analyzed for substrates; glucose, lactate, glycerol, amino acids and hormones; cortisol, glucagon, epinephrine, norepinephrine.
Before exercise, cortisol levels were 70% lower on the day after the use of metyrapone. Cortisol levels remained low during the two hours of exercise. Blood glucose and lactate levels were the same under both cortisol conditions. Blood glycerol increased more slowly during exercise under low cortisol conditions. Plasma amino acids were lower under low cortisol conditions, however their response to exercise was similar for both cortisol conditions. Plasma insulin levels will decline during an exercise bout, during an exercise bout under low cortisol levels, plasma insulin declines were even greater. Plasma glucagon was no different between the two conditions, however greater levels of epinephrine and norepinephrine were found in the low cortisol condition.
Higher blood glycerol levels are usually considered indicative of greater rates of lipolysis (i.e. fat mobilization from adipose tissue). Despite differences in blood glycerol during the normal and low cortisol conditions, there was no difference in substrate utilization (as assessed by respiratory quotient). In essence, regardless of whether blood cortisol increased or not during exercise, the amount of carbohydrates compared to the amount of fat that was being oxidized did not differ. The differences in plasma insulin, epinephrine and norepinephrine under low cortisol conditions suggests that redundant hormonal mechanisms kick in to maintain blood glucose, despite the lack of cortisol.
Commentary: The overall metabolic effects of cortisol during an exercise bout appear to be rather minor. Cortisol may even be considered a permissive hormone. That means that its direct effects are not as important as having a low level of the hormone around to ensure that other hormones have their effects. Regarding the switch in substrate utilization which occurs with exercise, from dependence of the muscles on glucose (carbohydrate) oxidation to more fat oxidation, cortisol appears to enhance the effects of epinephrine and norepinephrine. This metabolic switch is considered important for endurance activities and utilizing exercise as a therapeutic tool in weight management.
Although this was a small, but elegant study to try to clarify the physiological effects of cortisol on energy metabolism during exercise, perhaps other effects of cortisol are more important. As mentioned earlier the central nervous system effects (euphoria) and immune regulating effects may make cortisol elevations during exercise most helpful in appropriate recovery from the stress of exercise.
Impaired pituitary hormonal response to exhaustive exercise in overtrained endurance athletes
Med Sci Sports Exerc 30(3): 407, 1998.
Summary: Our understanding of overtraining is still immature. Hormonal responses to acute exercise bouts in endurance overtrained athletes over a period of time as not been previously studied. Seventeen male endurance-trained athletes (cyclists and triathletes) were recruited. At different times during a 19 month period the athletes were asked to increase their training frequency for several weeks. Once they felt they were overtrained they were asked to come to the laboratory for testing. A 30 minute bicycle ergometry test was performed in which periodic blood samples were taken. The blood samples were analyzed for cortisol and other hormones.
At rest the level of ACTH and cortisol was lower during overtraining compared with normal training, however this difference was not statistically significant. At the end of the exercise bout ACTH and cortisol were lower during overtraining compared to normal training. Exercise induced responses of epinephrine and norepinephrine were not different between the normal and over training condition.
Commentary: The results of this study suggest that overtrained endurance athletes have a blunted ACTH and cortisol response to an acute stress. Whether this can help account for the symptoms of fatigue, heavy feeling in legs during exercise or a decreased exercise endurance are unclear, but would seem likely. Clearly, overtraining negatively impacts the HPA axis. In particular it would seem that excessive, repeated stress has led to a relative weakened HPA axis response to stress. It would appear that even though physical stress has led to the weakened response, that the overtrained individual will be less able to deal with other stressors, physical or emotional. This may explain an increased susceptibility to upper respiratory tracts infections, since physiological levels of cortisol are known to help prevent infectious illness.
Perhaps the study of overtraining, used as a model for studying the physiological effects of excessive stress, can finally convince the orthodox medical community that there is such a syndrome as adrenal "burnout." That the symptoms of adrenal burnout are those now associated with overtraining. Fatigue, depression, insomnia, mood swings, weakness, etc. can be understood in physiological terms, not just psychological. The first treatment for HPA axis dysfunction is to delineate the stressors and remove them. Attending a seminar on coping skills is another way to improve one's ability to deal with life stresses. Perhaps if stresses can be dealt with "psychologically" then the physiological (HPA axis) response will not have to be as intense.
Column summary: Cortisol is the classic stress hormone. We would die without the ability to release cortisol in times of stress. Understanding the normal physiological effects and how the HPA axis is regulated is paramount to understanding how to better deal with life in the 20th century. Exercise represents a wonderful model by which to study the normal responses of the HPA axis to stress as well as the adaptations of the axis to repeated physiological stress.
It may be that moderate levels of regular exercise leads to a beneficial adaptive response of the HPA axis, so that other life stresses don't induce such a large HPA response. While excessive levels of exercise, i.e. overtraining, can lead to dysfunction of the axis leaving the athlete vulnerable to the effects of long term low cortisol.
Townsend Letter for Doctors & Patients.
~~~~~~~~
By Anna MacIntosh
Muscle Factor Training
A New Paradigm
You may be familiar with the old adage – heavy weights / low reps build strength & size, light weights / high reps build endurance. This belief about the effects that different numbers of repetition have on the body has been repeated for many, many years. I started lifting weights in 1982 and it was accepted as truth at that time. This belief is even accepted wisdom in the exercise physiology community. The exercise physiology textbook in my library, published in 1996, states, “Performing an exercise between 3-RM (repetition maximum) and 12-RM provides the most effective number of repetitions for increasing muscular strength.”(1) The bottom line is that there is little to no debate as to the effect different numbers of repetitions have on the body. If you want to increase strength and size, heavy weights and low reps is the universally agreed upon prescription.
From a practical perspective this has resulted in most or all resistance training programs recommending heavy weights and low reps exclusively. Basically every strength training or bodybuilding program recommends repetitions of 20 or less. During 15 years of following popular strength training literature I can recall only 2 instances where reps higher than 20 have been discussed and in only one of those instances was it even seriously recommended as a viable training method.
In the first case, in the early 1980s or so a professional bodybuilder (Johnny Fuller, if my memory serves me correctly) revealed that he preferred to train using 32 repetitions for most or all of his exercises. At the time this was used as an example of the recommendation that each trainee needs to find what works best for him/herself, but I don’t recall that the article recommended such high reps for anyone else. Nor did any follow on articles I ever saw suggest that trainees might experiment with reps in that high range.
In the second case, Muscle and Fitness magazine ran a few articles in the late 1980s about 100 repetition training. This series was run after one bodybuilder in particular revealed that he used 100 reps for brief training periods a few times a year. After that series of articles, I don’t recall ever hearing about this type of training again.
So, while the adage says heavy weight/low reps build strength and light weights/high reps build endurance, I do not believe that high rep strength training is commonly used or seriously considered as a viable training method by most trainees or their coaches. It isn’t commonly recommended to those who are most interested in increasing strength and/or size, nor does it seem to be a part of the serious endurance athletes training methods.
Since the adage says light weights / high reps building endurance, and increasing endurance is a goal of endurance athletes, I began wondering why high rep strength training was not commonly used by endurance athletes. Even though the primary goal of endurance athletes is to improve endurance, heavy weight / low rep strength training is what is most often recommended to them. The reason strength training is believed to be beneficial for endurance athletes is that it increases the amount of force produced during contraction, resulting in an increase in power output and, presumably, endurance performance. What about the second part of the adage though? The part that says light weights / high reps build endurance. One of the muscle factors contributing to power output is fatigue resistance. Increased resistance to fatigue is just another way of saying that the muscle’s endurance increased. I reasoned that if high rep resistance training really did increase endurance then perhaps it might be a beneficial training method for endurance athletes. With that thought in mind I started searching the available research to see what had been done on this topic. I found some exciting and surprising research for us to review. Let’s get to it.
Heavy weight/low rep vs. medium weight/medium rep vs. light weight/high rep
The first thing I wanted to know was whether research supported the belief that heavy weights / low reps build strength and that light weights / high reps build endurance. After all it wouldn’t be the first time that someone discovered that conventional wisdom was not completely accurate. I thought it best to be sure.
The classic research on this topic was conducted by Thomas DeLorme in 1945 (3). DeLorme’s research indicated that heavy weights do indeed build strength while higher reps build endurance. DeLorme is even credited with the axiom that heavy weights / low reps build strength and high reps / light weights build endurance. Quite a few other research studies on this topic have supported DeLorme’s findings hence the reason it is now accepted as conventional wisdom.
This is not to say that DeLorme’s original axiom has gone unchallenged though. Several research studies (4,5) that have found that the primary adaptation to either high or low reps is an increase in muscular strength. So even though it is accepted today that heavy weights / low reps builds strength and light weights / high reps builds endurance the fact is that some research has challenged this belief, suggesting that high reps primarily build strength, not endurance and resulting in conflicting data on the topic.
In 1982 two researchers from the University of Kentucky set out to resolve this conflict (6). Specifically, they wanted to determine the effects of three different resistance training protocols – heavy weights / low reps (6-8 reps), medium weight / medium reps (30-40 reps), and light weights / high reps (100-150 reps).
They recruited forty-three untrained, healthy subjects and trained them with the bench press exercise three times per week for nine weeks with one of three training protocols. The low rep group performed 3 sets x 6-8 reps maximum, the medium rep group performed 2 sets x 30-40 reps maximum, and the high rep group performed 1 set x 100-150 rep maximum. Resistance was adjusted as needed to ensure each subject stayed in the appropriate rep range through the training program.
Before training began each subject was tested for their individual 1 rep maximum (1-RM), relative endurance and absolute endurance. Relative endurance was determined by the maximum number of bench press repetitions they could complete with 40% of their 1-RM and adjusted as 1-RM changed, while absolute endurance was measured by how many reps could be completed with 27.23 kilograms.
At the end of the study all subjects were tested again for maximum strength, relative endurance, and absolute endurance. All three groups improved maximum strength and absolute endurance. The heavy weight / low rep group decreased in relative endurance while the other two groups increased relative endurance significantly. The results of this study are shown in table 1.
Table 1: Percent changes in max strength, absolute endurance, and relative endurance following strength training at three distinct repetition ranges
Training Group
% Change in Max Strength
% Change in Absolute Endurance
% Change in Relative Endurance
Heavy weight /
low rep
20.22
23.58
-6.99
Medium weight / medium rep
8.22
39.23
22.45
Light weight /
high rep
4.92
41.30
28.45
As can be seen from the data in table 1, the results of this study support DeLorme’s axiom. Heavy weight / low reps do build strength, while light weights / high reps build endurance. However, in contrast to DeLorme’s axiom, note that all 3 rep ranges resulted in increases in maximum strength. And all 3 rep ranges resulted in increases in endurance, with the exception of the relative endurance of the low rep group. So while low reps increase maximum strength more than do high reps and high reps increase endurance more than low reps the point is that resistance training significantly increases both strength and endurance. The researchers commented on this same point.
“The reader should note, however, that with the exception of the relative endurance task for the high resistance low repetition group, all training protocols demonstrated significant improvements on each of the three criterion tests.”
Anderson and Kearney’s research went a long way to resolving the conflicting data on DeLorme’s axiom – heavy weights increase strength the most, high reps influence endurance the most, but all resistance training results in improvements in both strength and endurance.
In 1994 Stone and Coulter modeled a study after Anderson and Kearney’s study with the exception of using a less extreme rep range for the high rep group (7). Stone and Coulter had their subjects perform either 3 x 6-8 reps, 2 x 15-20 reps, or 1 x 30-40 reps. The results of this program supported the findings of Anderson and Kearney. Strength and absolute endurance increased for all three groups. The low rep group improved strength more than the other 2 groups and the high rep group improved endurance more than the lower rep groups.
The bottom line is that while DeLorme’s basic axiom is generally supported by this research, the fact is that resistance training results in improvements in both strength and endurance but to varying degrees depending on how many repetitions are performed.
What about alternating rep ranges?
The studies cited above have compared one rep range to another, high reps vs. low reps for example. In every study researchers had subjects perform just one rep range and in each case heavy weights / low reps increased strength the most. What the researchers never examined was how a program of multiple rep ranges compared to a program consisting of a single rep range.
In 2004 a group of researchers tackled this very question in a fascinating study of varying combinations of high and low rep training (8). This group speculated that a combination type program that included both low and high reps would be more effective than a periodized program consisting of single repetition scheme during each training period or phase.
To test their hypothesis they recruited 17 untrained subjects, divided them into two groups, and then trained each group twice per week for 10 weeks. Subjects were tested for maximum strength and muscular endurance pre- and post-training. The first 6 weeks of training was designated as phase 1 and both groups trained exactly the same during this phase. Workouts consisted of two exercises (leg extensions & leg presses) for 3 sets x 10-15 reps. At the end of this first phase of training there was no difference between the groups; both had significantly and equally improved strength and endurance. This is not surprising since both groups trained exactly the same during phase 1.
During the final 4 weeks of the study, both groups conducted 5 sets x 3-5 reps of each exercise. One group, the combi-type group, added a single set of 25-35 reps following their final low rep set. At the end of the training program the combi-type group had increased their strength 58% more than did the other training group (14.7% vs. 9.3% respectively). The results are displayed in table 2.
Table 2: Set and rep ranges for 2 training phases and percent change in strength following phase 2.
Training Group
Phase 1 training
Phase 2 training
% Change in strength after phase 2
Strength type group
9 sets x 10-15 reps
5 sets x 3-5 reps
9.3 %
Combo type group
9 sets x 10-15 reps
5 sets x 3-5 reps,
1 set x 25-35 reps
14.7%
In their discussion of these findings, the researchers wrote,
“This suggests that the combi-type regimen caused a larger increase in dynamic muscular strength than did the strength-type regimen when combined with the hypertrophy-type regimen in a periodized fashion… This effect appears to be inconsistent with the classical principle operating in resistance-exercise training, in which low-repetition protocols are used for muscular strength and low-intensity, high-repetition protocols are used for muscular endurance. Sensible combinations of high- and low-intensity protocols may therefore be more important to optimize the strength adaptation to resistance training.”
There were also significant differences in endurance between the two groups. During phase 1 both groups increased endurance with no significant difference in the percent change. However, the combo type group’s endurance continued to increase during phase 2, while the strength type group’s endurance decreased 4.2%. The results are displayed in table 3.
Table 3: Percent change in endurance following each phase of training and total percent change in endurance.
Training Group
Change in endurance, phase 1
Change in endurance, phase 2
Total Change in Endurance
Strength type group
28.5 %
-4.7 %
24.3 %
Combo type group
20 %
18.8 %
38.2 %
In summary, this study found that a combination program consisting of heavy weights / low reps and light weight / high reps was more effective for improving both strength and endurance than a traditional periodized training program consisting of a single rep range during each training phase. This is truly a fascinating finding.
What Does All This Mean?
What are we to make of all this data on low and high rep strength training? Based on this data I suggest that the evidence supports that resistance training consisting of a combination of reps is superior to a more traditional lower-rep strength training program. While I’d like to see more research on this topic this data is enticing enough that I strongly recommend giving a combination of low rep / high rep training serious consideration.
Personally, I adopted a combination high and low rep program in 2007. At that time I had been strength training consistently for 25 years (I started in 1982) and had tried pretty much every training program that had come down the pipe. Changing to a combination program was the single best change I’ve ever made in terms of increasing strength. Despite being in my mid-40s and many years past my prime I was able to increase my strength to the level it had been at during my mid-20s. Too bad I didn’t discover this 25 years earlier.
What explains the results of a combination program? What physiologically is happening within the body that produces such large strength gains? Why does the addition of high rep training – training that has been conventionally viewed as endurance training – to a traditional low rep program produce greater gains in strength than a low rep program only? I pondered this question for about a year until I finally arrive at the muscle factor model as the physiological explanation. I believe this new model for how muscles function during exercise and how they adapt to exercise explains why a combination program is superior to single rep range training. Based on this I chose the term Muscle Factor Training to describe combination training.
If you would like to try muscle factor training I suggest starting with the following. In addition to the low rep training you are already doing, add:
one set of 20 reps (range of 17 – 23 reps)
one set of 40 reps (range of 35 – 45 reps)
For example, let’s say your current training program includes 4 x 8-10 reps in the bench press. You would replace 2 of those low rep sets with 1 set of 20 reps and 1 set of 40 reps. Your new bench press program would look like this:
2 sets x 8-10 reps
1 set x 20 reps
1 set x 40 reps
Summary
The old adage is that heavy weights / low reps build strength while light weights / high reps build endurance and a review of the research shows that the adage is basically true. However, while that adage is basically correct it does not reveal the complete picture. Strength increases from reps as high as 150 but if you are only doing one rep range then lower reps increase strength the most.
A combination of both high and low reps – what I call Muscle Factor Training – has been shown to increase strength significantly more than a traditional low rep, periodized type training program. For those who are most interested in maximizing muscular strength and size this finding is significant and should be seriously considered when designing a strength training program.
Reference:
1. Katch, Katch, McArdle, Exercise Physiology, Energy, Nutrition, and Human Performance, 1996, Williams & Wilkins, pg. 427
2. Muscle Limit Performance, Muscle Contractility
3. DeLorme, Thomas L., Restoration of muscle power by heavy resistance exercise, Journal of Bone and Joint Surgery, 1945, 27:645-667.
4. Stull G, Clarke D., High-resistance, low-repetition training as a determiner of strength and fatigability, Research Quarterly, 41(2), 189-193
5. Clarke D, Stull G., Endurance training as a determinant of strength and fatigability, Research Quarterly, 41(1), 19-26
6. Anderson T, Kearney J., Effects of Three Resistance Training Programs on Muscular Strength and Absolute and Relative Endurance, Research Quarterly for Exercise and Sport, 1982, 53:1, 1-7.
7. Stone WJ, Coulter SP., Strength/endurance effects from three resistance training protocols with women, J Strength Cond Res 8:231-234.
8. Goto K, Nagasawa M, Yanagisawa O, Kizuka T, Ishii N, Takamatsu K., Muscular Adaptations to Combinations of High- and Low-Intensity Resistance Exercises, J Strength Cond Res, 2004, 18(4), 730-737.
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[A] Training with heavy weights for strength is good, but you can and should train to failure in higher rep ranges as well. Not every muscle fiber responds to low-rep, heavy weight training. Flooding a muscle with growth-building hormones is all about a muscle pump (typically achieved with high-rep training), so that needs to be a part of your bodybuilding, too. Basically, your training approach is ultimately determined by what helps you build muscle, appear tighter and more separated, hold less fat and water, etc. Training with higher reps, in the 12–20-rep range, allows you to do high-volume workouts and can also enhance your muscular endurance. For example, Branch Warren and I will lift 250-pound dumbbells for 15–20 reps per set, but it takes time to build up to that level of endurance, just like it takes time to build up to a certain level of strength.
[Q] Johnnie, what effect does high-rep training have on your physique?
[A] It conditions you by quickly tapping out your glycogen stores, which is what you want to do. Afterward, you can have an anabolic creatine cocktail (I use HALO or Cell-Tech products by MuscleTech) to replenish what you’ve just used for instant muscle growth and recovery. Because of this training method, I’m the strongest I’ve ever been, although it could be the result of muscle maturity.
Testosterone, Lifting
Lifting weights increases testosterone. But the process of building muscle and gaining strength is much more complicated. The ratio of testosterone to cortisol influences results. Lifting weights modifies your hormonal profile.
Lifting weights:
Increases testosterone.
This has been measured in scientific research.
Lift Weights
Squats
In a study one group of men did 10 sets of 5 squats at 70% of their body weight. The other group of men did not lift weights at all. Testosterone and cortisol were measured in these men before, during and after their workouts.
The acute increase for [testosterone] is in agreement with previous reports that high power activities can elicit a [testosterone] response. High power resistance exercise protocols such as the one used in the present study produce acute increases of [testosterone].
Acute testosterone and cortisol responses
The men's testosterone levels increased after their weight lifting workouts. This is an acute increase of testosterone. This means that a light and fast weight lifting workout can increase testosterone afterwards.
These results indicate that high power resistance exercise can contribute to an anabolic hormonal response with this type of training, and may partially explain the muscle hypertrophy observed in athletes who routinely employ high power resistance exercise.
One interesting thing this study shows is that an increase in testosterone is found after even a high-repetition, light-weight workout. This means that lifting heavy is not the only way to build muscle.
So:
An increased level of testosterone, which leads to muscle growth, was found after high-repetition squats.
Squats
The men who participated in this study were trained. They were not beginners and probably had lots of experience lifting weights. They already had high levels of skeletal muscle. This could influence the study results.
Heavy lifting
Powerlifting is a sport that involves lifting extremely heavy weights. One study I found focused on elite powerlifters and how their testosterone and cortisol levels are influenced by lifting heavy.
After the weight lifting, cortisol was increased. As a reminder, cortisol is a catabolic hormone which tears down tissue—is a stress hormone. On the other hand, testosterone was not increased in the athletes.
No significant change in testosterone concentrations was observed during the experiment in either men or women, which resulted in a marked decrease in the testosterone/cortisol ratio.
Cortisol, DHEA and testosterone concentrations
This study reveals a fascinating piece of information about strength and muscle growth. Muscle is not entirely dependent on levels of testosterone. Strength is not just a matter of testosterone levels.
These extremely strong people—powerlifters—did not have an increase of testosterone levels after a meet. Instead their cortisol went up, which make the testosterone/cortisol ratio go down.
In conclusion, despite the increase in stress adrenocortical hormone responses to an international powerlifting competition, these hormone concentrations alone are not predictors of bench press performance in elite powerlifting athletes.
Testosterone-cortisol ratio
Several studies have shown that total testosterone does not increase significantly after weight lifting. But bioavailable testosterone may increase. This is because the testosterone/cortisol ratio is critical, not just testosterone.
Previous studies with different results have suggested that total and bioavailable testosterone levels are modified by physical exercise. Such changes may be related to modifications in cortisol levels and could be reflected in some urine androgens.
SHBG, plasma and urinary androgens in weight lifters
Something more interesting is going on with how weight lifting affects your hormones. What this study indicates is that exercise modifies your hormonal profile, changing your ratio of testosterone to cortisol.
Not only this, but your workout may change how your hormones are eliminated from your body. These changes are likely the ones that lead to increased muscle mass. They will also lead to less fat mass.
These results suggest that intense physical activity may have an influence on the elimination of androgenic hormones due mainly to changes in their transporting protein SHBG.
Rest periods
Are rest periods during your weight training workout necessary? Some trainers will encourage people to rest several seconds or minutes between sets of lifting. In my research I found one scientific study that supports this idea.
The study, done in Iran, measured testosterone and growth hormone in two groups of men. One group lifted weights with no rest periods. The other group lifted weights with repeated rest periods.
The results of the present study support rest period in [resistance exercise] sets as an important variable to increase the anabolic hormone concentrations, and it should be mentioned that short rest intervals elevated greater increase in [growth hormone] concentration compared with 120-second rest. However, [testosterone] response was greater in the [resistance exercise] protocol with a 120-second rest interval between sets.
Effects of very short rest periods
Men who rested only 60 seconds between sets of their exercises—squat and bench press—gained the most growth hormone. But men who rested 120 seconds—two minutes—between sets of their exercises gained the most testosterone.
Therefore:
This study provides a good reason to take rest breaks while lifting weights.
Tip:
Waiting one or two minutes between sets of your lifts is a way to increase your growth hormone and testosterone responses.
And:
This will yield greater strength and mass gains for your athletic goals. More information about growth hormone is available.
Growth Hormone
Beginners
A medical study also found that resting one minute between sets of weight lifting caused the best hormone response. But this difference disappeared after ten weeks of weight lifting. It only helped beginners.
Info:
It is unclear if rest periods are only important while your body adapts to lifting, or if other factors are dominant.
These results show that in healthy, recently untrained males, strength training with 1 minute of rest between sets elicits a greater hormonal response than 2.5-minute rest intervals in the first week of training, but these differences diminish by week 5 and disappear by week 10 of training.
Supplements
Food is critical to your bodybuilding efforts. For this reason, knowing how supplements affect your testosterone levels after lifting is useful. Total testosterone is diminished by consuming carbohydrates after a workout.
Ingesting [carbohydrate] after resistance exercise resulted in decreased [total testosterone] concentrations during recovery, although the mechanism is unclear.
Hormonal response to carbohydrate supplementation
Unclear—this is the key word of this study's results. Consuming carbohydrates after weight training will decrease total testosterone, but it is unknown why this occurs. Our understanding is limited.
Note:
The equation is not simple. Weight lifting and supplementation does not directly increase testosterone.
Lift twice daily
Some enthusiastic trainees will try lifting weights twice each day to improve their results. Often this approach is not successful. One scientific study analyzes its effects on hormones such as testosterone.
There were also no significant group differences when parameters were expressed as percentage change, but the twice-daily training group had a greater percentage change in [knee strength], [neuromuscular strength], testosterone, and testosterone/cortisol ratio than did the once-daily training group.
Comparisons between twice-daily and once-daily
The weight lifters who lifted twice a day had more testosterone, and a more favorable testosterone to cortisol ratio. The T increase in the twice-daily group was 10.5%. In the one-daily group it was 6.4%.
National-level male weightlifters. This study was done on national-level male weightlifters: the best of the best. And the divided training schedule had limited benefits for these men.
How Often to Lift Weights
Story:
I once tried lifting weights every day. This quickly led me to overtraining and exhaustion.
And:
My strength dramatically went down. I don't recommend daily (or twice-daily) lifting for anyone near a normal fitness level.
Young, old
In fitness and health, your age has a profound effect on your response to physical training. Despite this, one study shows that both young and old men have a hormonal response to weight lifting.
In the study, the old men were on average 69 years old. The young men were 23 years old. For both groups, a moderate intensity and high repetition weight lifting workout increased testosterone and growth hormone.
A resistance exercise protocol for the improvement of strength endurance seems to be a sufficient stimulus that increases testosterone, growth hormone and cortisol concentrations in elderly males.... The elderly subjects present an attenuated growth hormone response compared to younger ones.
Hormonal responses after exercise
Older men have an attenuated response of growth hormone and testosterone to exercise. For this reason, it is wise not to be too critical of people older than you are. They actually have a less favorable hormonal profile.
Also:
Even if they do work out, they will receive fewer benefits from it than a younger man.
Summary
When we lift, testosterone levels are affected. A complex interplay of growth hormone, testosterone, physical activity and other factors inside your body determine muscle growth. It is worthwhile to rest between sets of lifting.
And:
It is not necessary to lift extremely heavy weights to increase testosterone.
Increase Testosterone
Strong: Testosterone http://www.stronghealthtips.com/testosterone-weight-lifting
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Does the number of reps and sets of a weight lifting program affect hormonal response?
Friday, April 09, 2010
There are still a lot of aspects scientists do not understand regarding the muscle growth process. One of those “grey” areas is the body’s hormonal response to resistance training and what it means in the big picture of gaining muscle mass.
A number of studies indicate that the structure of a program (reps, sets and amount of weight utilized) can influence the hormone response.
For example, the amount of overload used in training seems to influence circulating testosterone concentrations. The greater the overload used – the larger the increase in circulating testosterone. However, data on the other anabolic hormone, growth hormone, is less clear.
Some studies report an elevation in circulating growth hormone secretion with higher rep’ training (12-15 reps). However, these studies also show that cortisol levels increase in proportion to the volume of work performed in a workout. Elevated cortisol levels are something bodybuilders want to avoid. Consistently high cortisol levels make it impossible to recover and build muscle. High cortisol levels are also a characteristic of overtraining.
Greek researchers have recently discovered that using high overload/lower-rep (6 or less) bodybuilding workouts produce a sharp increase in growth hormone, and these increases are equal to that seen with high-volume, high-rep’ workouts. Interestingly, the increases in growth hormone witnessed with high-overload/low-rep training were achieved without the high cortisol levels seen with high-rep/high-volume training.
Limiting cortisol secretion by eliminating needless sets and reps will probably result in much better strength and lean mass gains in the long term. Maximum overload without needless volume appears to be a research-based prescription for the right hormonal environment that optimizes muscle gains from training.
Shorter training sessions. While we might think more is more when it comes to hitting the gym, keeping workouts short is one of the best ways to control cortisol. Cortisol is released by the body in response to stress, and strength training sessions shorter than 45 – 60 minutes have been demonstrated to minimize this. Similarly, cortisol is best controlled by cardio sessions shorter than 30 – 45 minutes. Going to the gym should be part of your day – not the whole day.
Eat carbs when it counts. When it comes to nutrition, it’s important to recognize the inverse relationship between glycogen and cortisol. As glycogen levels go down, cortisol goes up. When your body runs out of glycogen – which it uses for energy – the increase in cortisol triggers a breakdown of protein (stored as muscle) to be converted to fuel. It’s not a good thing for people trying to build muscle, but it can be avoided by eating first thing in the morning and consuming carbs immediately after a workout. When taking your post-workout protein shake, ensure that you are also getting some simple carbohydrates that can be absorbed quickly.
Manage stress. Since cortisol is released in response to stress, managing your stress levels outside of the gym will be helpful. This may mean setting aside time for meditation, bubble baths or even a massage.
Get enough sleep. Cortisol levels are lowest (and growth hormone levels are highest) in the deepest phase of sleep. Get your required 7 – 8 hours, and do your best to ensure that it’s uninterrupted (i.e., put your phone on silent).
Supplement. A 2001 study by Peters, Anderson & Theron concluded that getting 3 grams of Vitamin C a day helps lower cortisol levels. It’s also believed that supplementing with glutamine may help. If you’re concerned, you may wish to consider these options.
