A new study has exposed as myth the popular belief that increased levels of hormones after intense weight-training sessions play a key role in building muscles.
Researchers at McMaster University have found that exercise-induced testosterone and growth hormone do not play any influential role in building muscle after weightlifting.
Testosterone - a steroid hormone secreted in the testes of males and the ovaries of females - is essential for sexual development and for gaining muscle mass and energy. Growth hormone is a peptide hormone that stimulates growth and cell reproduction, and these two hormones are considered very important to quality of life.
Study author Daniel West says trying to manipulate these anabolic hormones through exercises is a sheer waste of time.
Two separate studies comprised the research. In the first study, men and women were subjected to intense leg exercise. All though there was a 45-fold difference in testosterone increase, the men and women were able to make new muscle protein at exactly the same rate.
"While testosterone is definitely anabolic and promotes muscle growth in men and women at high doses, such as those used during steroid abuse, our findings show that naturally occurring levels of testosterone do not influence the rate of muscle protein synthesis," West noted.
In the second study, 56 young men aged 18-30 trained five days a week for 12 weeks, and the researchers analyzed their hormonal responses post exercise. Some men gained up to 12 pounds of muscle mass, while some virtually nothing. But, their muscle growth and strength gain did not show any relationship to the levels of testosterone and growth hormone.
A surprising find by the researchers was that cortisol - a steroid hormone which reduces protein synthesis and breaks down tissue - was related to gain in muscle mass.
The studies were published in the Journal of Applied Physiology and the European Journal of Applied Physiology.
by RTT Staff Writer
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