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Bulletin #76 – Cortisol Suppression: Muscle Myth of Nutritional Reality

Most everyone knows that testosterone is one of the principle hormones respon-sible for muscle growth and most have also heard of cortisol. They might have some vague idea that cortisol is bad in so far as muscle growth; but few could tell you exactly what cortisol is much less how to control it. This month I thought I would explain what cortisol is and what we can do to favorably manipulate it. Cortisol is a steroid hormone manufac-tured by the adrenal glands. It is not ana-bolic like testosterone; to the contrary, cortisol is primarily catabolic. Before you rush off to the doctor to have your adre-nal glands removed, realize that cortisol (despite the negativity attached to catabo-lism) is essential for human existence. One of the simplest ways to understand the diverse effects of cortisol is to look at a couple of diseases related to cortisol pro-duction. When someone is afflicted with Addison’s Disease, the body is unable to produce cortisol (1). This promptly re-sults in hypotension (low blood pressure), shock, and eventual death. There are a va-riety of substances the body produces to control blood pressure and some of them work by binding to receptors on the blood vessel walls.

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Without cortisol these recep-tors become insensitive to the substances that normally bind and hypotension and death can develop. By injecting the suf-ferer with a shot of cortisol (or a synthetic version) this potentially deadly situation can be quickly brought under control. Without any cortisol in your system you would die within a day or two. At the other extreme is Cushing’s Dis-ease, a condition caused by excess corti-sol (1). Cushing’s sufferers become obese and develop diabetes (cortisol causes in-sulin resistance) and osteoporosis. They also experience severe muscle wasting and may become so weak they are barely able to walk. Sufferers develop very ten-der skin and bruise easily and profusely. Edematous causes those with Cushing’s Disease to retain water and become puffy. These unfortunate people develop a char-acteristic body shape called the “Cushin-goid habitus,” characterized by very thin arms and legs (from the muscle wasting), coupled with a large, obese abdomen and a round, puffy face.

This disease can be mimicked by giving someone prednisone, a synthetic form of cortisol. This drug is used to treat rheumatoid arthritis, lupus, asthma and a variety of other inflamma-tory diseases. Patients who require large doses of prednisone for a prolonged time develop syndromes virtually identical to Cushing’s Disease. The bottom line on cortisol is simple: too much and you will risk muscle wasting and obesity. Not enough cortisol can also give you massive medical problems. We need to strike a happy medium. For-tunately, as long as your adrenal glands are functioning properly, you’ll never have to worry about cortisol deprivation or excess. Your adrenal glands, in concert with other glands (and nature), automati-cally regulate cortisol and keep it in the appropriate range. So why am I bothering to write about this obscure subject? It turns out that exercise increases cortisol levels and this has important implica-tions that need to be taken into account by anyone who practices high intensity weight training. Exercise stimulates mus-cle growth and paradoxically also triggers the release of cortisol.

When cortisol is suddenly dumped into the bloodstream it is a potentially catabolic situation. So we need to understand how cortisol works and how it is regulated so we can design a training and nutrition strategy which will allow for optimal growth while mini-mizing cortisol’s catabolic effects. So let’s begin with a brief summary of how cortisol secretion is regulated (1). The adrenal glands receive a signal to produce cortisol from an endocrine gland in the brain called the pituitary gland. This chemical signal is called ATCH and travels from the pituitary to the adrenals via the bloodstream. ATCH activates the adrenals to produce cortisol . The pituitary is in turn regulated by CRH originating in the hypothalamus . The hypothalamus and pituitary glands are part of the brain and serve to control the endocrine system. These glands coordinate the activity of the endocrine system with the nervous system. The hypothalamus releases CRH, which stimulates the pituitary to release ATCH . This stimulates the adrenal glands to release cortisol.

As blood cortisol levels increase, some of it circulates back to the hypothalamus . The hypothalamus senses the cortisol concentration and determines when to shut down CRH release, which brings the cycle to a halt. When cortisol levels drop too low, or when the body faces a new stress, this again activates the hypothalamus to produce CRH and the cycle begins again. This is how cortisol is produced and regulated . Various stimuli can cause this pathway to become up-regulated thereby increas-ing cortisol levels. These stimuli can include any form of stress on the body such as injury, burns, illness, infection, fever, starvation and exercise (1). Cortisol is a hormone whose overall function is to help the body deal with stress. Cortisol has a wide variety of actions, all of which help to regulate overall metabolism. This is why any extreme cortisol deficiency will result in metabolic and physiologic collapse and eventual death. What is cor-tisol’s defining actions? Cortisol has a di-rect effect in regulating carbohydrate, fat, and protein metabolism (1).

Cortisol mo-bilizes the body’s energy reserves during times of stress. Cortisol acts to increase blood glucose concentration in two ways: first, through a decrease in insulin sensi-tivity (thus reducing storage of glucose inside cells) and second, by stimulating gluconeogenesis . Gluconeogenesis is the production of new glucose from amino acids. Unfortu-nately, these particular amino acids are derived from the breakdown (catabolism) of body proteins including muscle tis-sue. Cortisol stimulates muscle catabo-lism to free up the amino acids so they are available to be converted into glucose to use for energy. This is why excess cortisol causes muscle wasting. Cortisol’s effect on body fat varies somewhat according to the specific body region. Fat depots exist in different parts of the body and these different regions have different hormone receptors . Cortisol tends to cause deple-tion of peripheral fat in the arms and legs, but increased accumulation of fat in the abdomen, back and face. Patients with excessive cortisol levels (or those on high dosages of prednisone) develop thin arms and legs due to both muscle and fat loss (through catabolism).

Typically, they also develop obese abdomens. Cortisol has a powerful effect on modulating the immune system (1). It does this by suppressing cytokine forma-tion. Cytokines are messages exchanged between immune cells as they commu-nicate to activate the immune response to injury, illness, or infection. Cortisol blocks the formation of these messages, greatly attenuating the immune response . This is why prednisone is so widely used to control autoimmune diseases such as rheumatoid arthritis and lupus. In these diseases the immune system is over-ac-tive and the body attacks itself. Cortisol helps control metabolism and cortisol also works to modulate the activity of the immune system . Cortisol also helps control fluid and water balance (1). The general effect is to cause more water to accumulate in the interstitial space . This is the space outside of the individual cells: the space between cells. When wa-ter accumulates between cells it is called edema: an extreme form of the puffiness and water retention exactly what a competitive bodybuilder strives to avoid before competition.

Now that we have some background on what cortisol is, where it comes from, how it is regulated, and what it does we can talk about what we can do to mini-mize it’s undesirable effects. For body-building purposes we want to minimize cortisol because it promotes muscle loss, fat accumulation and water retention. Cortisol is secreted in response to stress of almost any kind. It should then come as no surprise that the first thing we should do to control cortisol is minimize body stress and maximize recovery time. For starters, get plenty of rest. Sleep depriva-tion has been shown to increase cortisol levels and the reintroduction of proper sleep habits reduces cortisol levels back to normal. Everyone knows either by in-tuition or experience that muscle growth is much harder if you don’t get enough rest . And don’t neglect the connection between cortisol and stress. Anger and stress are often interrelated: are you a “type A” personality? If so, attempt to remain as relaxed and calm as possible. Easier said than done. Remember this: ev-ery time you have an emotional outburst, lose your temper or fly into a rage, you are most likely dumping huge amounts of muscle-eating cortisol into your blood-stream. Hopefully, that thought will give you pause if you are serious about body-building but emotional by nature. Another cortisol-related factor is train-ing.

Over-training, literally doing too much training, while being under nour-ished and not getting enough rest re-sults in decreased testosterone produc-tion and increased cortisol levels. This tips the balance rapidly from anabolism to catabolism. People who are chroni-cally over-trained are continually tired, fatigued, weak and often depressed. They lose muscle, strength plummets and per-formance declines. If you look around the gym, the people who are not mak-ing progress are usually under-training not over-training. Furthermore, if you compare the stagnant trainers to the one making the gains, you will observe the ones making gains are invariably training harder and longer. Before you conclude that you are over-training and reduce your exercise level, try getting some additional rest, eat more clean calories and add in some basic supplements to increase your nutrient levels. Generally these changes will promote growth without having to reduce exercise activity.

In many cases, failure to grow is simply the result of inadequate caloric and nutrient intake in relation to the exercise level of the body-builder. Over-training is a result of doing too much exercise (volume) while being under nourished. Do not confuse volume with intensity. Successful bodybuilding is about intensity, not volume. Endurance exercise is about volume, not intensity. You should train intensely and workout for 60 to 90 minutes. There are certain nutrition and supple-mentation strategies you can use to mini-mize the catabolic effects of cortisol. The single most important and effective of the cortisol-suppressing nutritional tech-niques is a low-tech solution. Probably the most effective thing you can do to minimize cortisol release is to simply eat something every two to three hours. Caloric deprivation has been shown to cause a significant increase in cortisol levels (3). A small meal every two to three hours (or so) is a great way to keep cortisol excretions to a minimum. The ideal cortisol suppressing meal would contain a complex carbohydrate and some protein.

Carbohydrate ingestion in par-ticular seems to reduce cortisol levels. It is also important to eat some protein at each meal as protein slows the release of carbohydrates and provides a constant supply of amino acids to facilitate muscle growth. Most people find it difficult to eat six complete meals a day and rely on nu-tritional supplements for two or three of these many meals. If you are looking for a supplemental meal replacement try our 50-50 Plus™. This fantastic product sup-plies 17 grams of quality carbohydrates and 20 grams of high BV protein. Another excellent meal alternative is the Parrillo Bar, Parrillo Protein Bar or the New Par-rillo Energy Bar. These tasty bars are ex-tremely convenient and will provide you with a balanced meal that you can carry in your pocket and eat in minutes. Some of our athletes like to combine Optimized Whey Protein™ or Hi-Protein Powder™ with Pro-Carb™. This novel approach allows you to customize and adjust your ratio of protein-to-carbohydrates to suit your personal goals . Frequent caloric intake (particularly carbohydrates) seems to be the most im-portant nutritional intervention tactic we can use to reduce cortisol levels. In addition, vitamin supplementation may be helpful.

In particular, the antioxidant vitamins E and C seem to reduce the oxi-dative stress of exercise and therefore re-duce catabolism. Most bodybuilders who follow our nutritional guidelines don’t eat fruit (since fruit sugar is preferentially converted into fat) and therefore vitamin supplementation becomes an even better idea. Glutamine and the branched chain amino acids leucine, isoleucine, and valine may not affect cortisol levels directly, but are very effective at shifting the anabolism-catabolism balance more towards the anabolic side. These amino acids seem to have a powerful effect in stimulating protein synthesis . Glutamine has been shown to increase glycogen storage as well as increase growth hor-mone levels (3,4). Our protein products (Optimized Whey™, Hi-Protein™, 50-50 Plus™) all have high amounts of amino acids mixed into a well-balanced protein base. Recent research suggests that a special lipid called phosphatidylserine (PS) may decrease the exercise-induced cortisol significantly (5,6). We’ll keep you posted on this development.

In summary: to help minimize the catabolic effects of cortisol you should get plenty of rest, minimize stress in your life and avoid over-train-ing. You should eat small, frequent meals, containing both carbohydrates and pro-tein . Your protein choices should contain high levels of glutamine and the BCAAs. Try to eat every three hours if possible. Three conventional meals per day, com-bined with three servings of 50-50 Plus™ or your own Pro Carb™/Hi-Protein™ or Optimized Whey concoction will assure that you are obtaining adequate protein intake and obtaining high levels of glutamine. By applying and following a few common sense diet and exercise guidelines, we can minimize the catabolic Cortisol Suppression: Muscle Myth or Nutritional Reality?effects of cortisol. Just remember to stay cool calm and collected the next time the boss or your kids do something that makes you angry. By subduing stress, getting plenty of rest, adequate nutrients and exercising hard and intensely, corti-sol-related muscle wasting can be a non-event in your bodybuilding career.


1. Fauci et al. Harrison’s Principles of Internal Medicine. McGraw Hill, New York, 1998.

2. Kelley DS et al. Energy restriction and immunocompetence in overweight women. Nutrition Research 18: 159-169, 1998 .

3. Varnier M et al. Stimulatory effect of glutamine on glycogen accumulation in human skeletal muscle. Am. J. Physiol. 269: E309-E315, 1995 .

4. Welbourne TC. Increased plasma bi-carbonate and growth hormone after an oral glutamine load. Am. J. Clin. Nutr. 61: 1058-1061, 1995 .

5. Monteleone P, Maj M, Beinat L, Natale M, and Kemali D. Blunting by chronic phosphatidylserine administration of the stress-induced activation of the hypo-thalamo-pituitary-adrenal axis in healthy men. European Journal of Clinical Phar-macology . 42: 385-388, 1992 .

6. Monteleone P, Beinat L, Tanzillo C, Maj M, and Kemali D. Effects of phos-phatidylserine on the neuroendocrine re-sponse to physical stress in humans. Neu-roendocrinology 52: 243-248, 1990 .

2018-03-13T11:10:31-04:00 June 17th, 2009|Technical Supplement Bulletins|

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