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  • 标题:Cortisol control: what salmon can teach you about proper training and recovery
  • 作者:Shawn Talbott
  • 期刊名称:American Fitness
  • 印刷版ISSN:0893-5238
  • 出版年度:2003
  • 卷号:Nov-Dec 2003
  • 出版社:Aerobics and Fitness Association of America

Cortisol control: what salmon can teach you about proper training and recovery

Shawn Talbott

Consider the plight of Atlantic salmon--swimming, leaping and flopping their way upstream to spawn. As they exert themselves at this high rate, levels of cortisol (i.e., the body's primary stress hormone) surge through every body system to help provide energy and drive the "fight or flight" response that keeps them going. If the salmon could stop to catch their breaths, refuel their tanks and get some much-needed rest, those cortisol levels would lower to normal. Unfortunately, since they have some spawning to do, they press onward and their cortisol levels remain elevated during their multi-week, upstream workout. Upon reaching their spawning grounds, they get it over with and promptly die.

If you took a close look at these just-spawned salmon, you'd notice one striking feature--they're a mess! These fish suffer from immune system breakdown, infections, open sores, muscle loss and brain destruction. Why is this important? Because the same hormonal stress response and elevated cortisol levels may occur in your body when you exercise. In many ways, the salmon are a perfect example of the dangers of overtraining and cortisol overexposure.

Chronically elevated cortisol levels lead to muscle loss, fat gain, immune suppression and reduced ability to repair tissue damage following intense workouts--and these are just some of the effects on athletic performance. Prolonged stress and curtisol exposure can also damage heart and blood vessels, shrink brain cells, break down bone tissue and increase the risk of depression, diabetes and other illnesses. Fortunately, there are many ways to control cortisol levels and these strategies can simultaneously benefit health and performance.

WHO HAS ELEVATED CORTISOL LEVELS?

Are you exposed to stressful events on a regular (i.e., daily) basis? Do you sleep less than eight hours each night? Are you watching your weight? If you answered "yes" to any of these questions, you may have chronically elevated cortisol levels. To gauge your cortisol levels, visit www.cortisolconnection.com to take a Cortisol Self-Test.

CORTISOL AND METABOLISM

Among its many other functions, cortisol stimulates glucose, fat and amino acid release for energy production. In the liver, cortisol triggers the breakdown of glycogen into glucose and in adipose tissue (i.e., where body fat is stored) fatty acids are released. Although fat breakdown sounds good, chronic cortisol exposure results in fat gain. Cortisol also promotes amino acid release in the skeletal muscles, which they use directly for energy or the liver converts to glucose. If this process continues for a prolonged period of time, a significant amount of muscle mass may be lost, which is bad for immediate peril, finance as well as long-term weight maintenance.

If muscle loss isn't enough bad news, chronic cortisol exposure also increases appetite and cravings for certain foods--especially sweets. Since one of cortisol's primary roles is to encourage the body to refuel after responding to a stressor, an elevated cortisol level keeps your appetite ramped up, so you almost constantly feel hungry. In addition, the fat developed as a result of this stress-induced appetite will typically accumulate in the abdominal region, where it can be readily accessed during other forms of stress, such as starvation. Since few of us are faced with starvation, this cortisol-induced fat remains around our middles. The major problem with excess abdominal fat, aside from the fact that nobody wants a potbelly, is it is highly associated with the development of heart disease, diabetes and cancer.

COUNTERACTING THE EFFECTS OF CHRONIC STRESS

Fortunately, numerous approaches can counteract and/or prevent cortisol's detrimental effects. From my bias as a physiologist and nutritionist, I believe you get the "biggest cortisol-controlling bang for your buck" from a combination of adequate exercise, recovery, nutrition and selected dietary supplements (i.e., taking some and avoiding others).

EXERCISE

The good news for athletes and exercisers is being active can help reduce some of cortisol's detrimental effects. Exercise induces the production of dopamine, serotonin and endorphins--the "feel-good," anti-anxiety and anti-depression chemicals responsible for "runner's high." Researchers at Duke University have shown exercise (30 minutes per day, three to four days a week, for four months) can relieve anxiety and depression symptoms as effectively as prescription antidepressants.

In addition to exercise making you "feel" better, exercise can change the way your body produces and responds to cortisol. For example, while an acute exercise bout will elevate your cortisol levels, adhering to a regular exercise program will slowly "teach" your body to produce less cortisol in response to a given workload. This effect is due to an increase in cortisol sensitivity in muscles and other tissues. Without cortisol overexposure, tissues can more easily balance their exposure to free radicals and inflammatory cytokines. Consequently, muscle tissue can recover and adapt faster following exercise and adipose tissue can more readily release its stored fat.

RECOVERY

Researchers at the University of Colorado have conducted several studies showing how moderate exercise can reduce many detrimental effects of chronic stress. Regular moderate exercise can reduce body fat, build muscle and bone, improve mental and emotional function, stimulate immune response as well as reduce appetite. However, they also found that exercise extremes (studied in overtrained endurance athletes) can reverse these benefits by elevating cortisol levels, increasing body fat and injury risk, interfering with mental and emotional function as well as suppressing immune function. People who train excessively and/or recover inadequately tend to carry more body fat and less lean muscle mass than those who have a better balance between training and recovery.

NUTRITION

Proper nutrition also plays an important role in counteracting cortisol's effects. A common saying among sports nutritionists is "there is no such thing as overtraining--only under-eating" because a proper diet can help control cortisol, modulate inflammatory responses, promote tissue repair and prevent overtraining syndromes. However, when it comes to "proper" diet, things can get a bit complicated. Fortunately, we can simplify matters a great deal by consuming protein, carbs, Fats and fiber at every meal.

In terms of protein and carbohydrate needs, research over the past decade indicates people who do a moderate amount of regular exercise (i.e., weekend warriors and recreational exercisers) need more protein and carbohydrate to satisfy energy needs and tissue maintenance. Putting together the mathematical mumbo-jumbo will have you consuming four to six meals/snacks per day composed of 20 to 30 grams of protein, 50 to 100 grams of carbohydrate (depending on body size and training status) and five to 10 grants of fat. This works out to 325 to 610 calories per meal, which provides optimal blood-sugar control, appetite regulation, fat metabolism, energy levels and mood in addition to the primary cortisol control benefit.

DIETARY SUPPLEMENTS

With all this emphasis on balancing exercise with adequate recovery and eating the right amount of macronutrients for energy and tissue repair, where do dietary supplements fit in? Aside from avoiding stimulants, such as caffeine, ephedra and synephrine (which can increase cortisol levels when used for more than a few weeks), a variety of dietary supplements can help keep cortisol levels within normal ranges, even when a person is stressed. The first step is to take a daily multivitamin/mineral containing, at a minimum, calcium, magnesium, vitamin C and B-complex vitamins to help modulate the general stress response. For specific cortisol control, the most effective supplements include a variety of plant extracts, such as magnolia bark, epimedium, theanine, beta-sitosterol and phosphatidylserine. Many of these natural products provide a convenient approach for many people subjected to daily emotional and physical stressors.

SUMMARY

For most of us, removing stress from our lives is unrealistic. We have to work (stress!), pay our bills on time (stress!), sit in rush-hour traffic (stress!) and deal with family and interpersonal relationships that don't always go smoothly (stress!). On top of that, we try to train and perform at our optimal levels (even more stress). By correctly combining proper training, recovery, nutrition and supplementation, we can manage stress, control cortisol levels and promote not only optimal physical and mental performance, but also long-term health. Remember, it's OK to eat the salmon and it's even OK to save the salmon--just do whatever you can to not be the salmon.

RELATED ARTICLE: Short-term vs. long-term cortisol exposure.

Short-term cortisol exposure (seconds to minutes, as you might experience from moderate levels of exercise) causes:

* glycogen breakdown

* increased blood sugar

* fat tissue breakdown

* elevated blood pressure

* improved cardiovascular dynamics (i.e., stronger heart contractions, etc.).

Each of the above factors is a "good" thing while you are exercising--but you want these metabolic parameters to return to baseline levels after exercising.

Chronic cortisol exposure (hours to days to weeks, as you might experience from overtraining, psychological stressors, excessive dieting or too little sleep) causes:

* increased blood sugar

* accelerated muscle tissue breakdown

* accelerated connective tissue breakdown (bones, tendons, ligaments, cartilage, skin)

* suppressed immune system function

* increased fat storage.

The "moral" of the story is that cortisol is neither "bad" nor "good"--the length of your exposure is what matters. During chronic cortisol exposure, we "shift" or "up" from cortisol being a fat-loss stimulus to it being a signal for fat-gain and muscle loss. Furthermore, it can disrupt numerous body systems.

Shawn Talbott, Ph.D., an avid Ironman triathlete, is an adjunct assistant professor of nutrition at the University of Utah and the author of The Cortisol Connection: Why stress makes you fat and ruins your health (Hunter House, 2002). He lives, trains and controls his cortisol in Salt Lake City.

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COPYRIGHT 2004 Gale Group

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