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Relaxation exercise halves cortisol level

Athletes seeking to maximise muscle growth may benefit from simple relaxation exercises. At least, you can deduce this from research done by psychologists at the University of Southern Mississippi, published in Biological Psychology. The results showed that a 15-minute relaxation exercise almost halved the cortisol level [structural formula shown below] in healthy people.

Strength athletes' progress depends to a large extent on how their hormone system reacts to training. The more anabolic hormones athletes produce (growth hormone and testosterone) and the less catabolic hormones (cortisol), the greater their progression will be.

The dilemma that athletes face, however, is that training schedules that result in more testosterone and growth hormone usually push up cortisol levels as well. That's why trainers and gurus are interested in just about anything that will inhibit cortisol production during training, whether that's taking in sugars during training, using designer supplements or plant compounds like the flavonoid quercetin.

But there are also ways of reducing cortisol production during training that have nothing to do with pills, such as Transcendental Meditation or anti-stress techniques. According to some studies, even chewing gum can reduce cortisol producing during stressful events.

In the article published in 2002, the Americans examined the effect of a simple relaxation exercise Abbreviated Progressive Relaxation Training (APRT) on forty test subjects. APRT consists of lying down and contracting specific muscle groups for seven seconds and then completely relaxing them for thirty seconds, while focusing your awareness on the experience of contracting and relaxing the muscle groups.

There is a fixed sequence in which you contract and relax the muscle groups. You start with your upper right arm and then go on to your left lower arm, left upper arm, forehead, muscles around your nose, jaw muscles, neck, chest, shoulders, upper back, stomach and then on to your right leg, ending with your left leg.

The test subjects did two sessions, with a week between the two. The researchers measured the cortisol concentration in the test subjects' saliva before and after the sessions. A control group just sat quietly on a chair.

The figure below shows the effect of the first [Experimental Day 1] and the second [Experimental Day 8] relaxation exercise. The right hand side bars show the effects of sitting on a chair [Control].

Relaxation exercise halves cortisol level

The cortisol measurements for Control Day 8 are on the low side. According to the researchers this is due to the time at which the experiment was done: the later in the day, the less cortisol the body produces.

The researchers were primarily interested in finding out whether APRT can boost the immune system. Cortisol inhibits the immune system, so the effects measured look promising. "These results indicate that a behavioral manipulation of the body's stress hormone is possible", the researchers conclude. "The clinical implications for possible uses of relaxation as an inexpensive, effective means of improving people's health are enormous."

The subjects didn't do any training. But you wonder of course whether strength athletes could reduce their cortisol levels more quickly after training by doing a simple relaxation exercise and thereby improve their muscle growth.

Biol Psychol. 2002;60(1):1-16.

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