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Cutting Back on Sleep Lowers Testosterone Levels in Young Men, Study Finds
By Jennifer Warner
WebMD Health News
Reviewed by Laura J. Martin, MD
June 3, 2011 -- Cutting back on sleep, even for a little while, may have a dramatic effect on men's testosterone levels.
A preliminary new study shows a week of sleep loss lowered testosterone levels by up to 15% in group of healthy young men.
Testosterone is also critical to building muscle mass and strength and bone density. Testosterone levels naturally decline in men aged 40 and over by about 1% to 2% per year.
Sleep Affects Testosterone Levels
In the study, published in the Journal of the American Medical Association, researchers compared testosterone levels in a group of 10 healthy young men after a week of normal sleep and a week of sleep loss.
In the first week, the participants slept eight hours each night at home. Then they had three nights of 10-hour sleep and eight nights of 5-hour sleep in a sleep laboratory.
The results showed that testosterone levels decreased by 10%-15% after the week of sleep loss compared with their rested states. This decrease in testosterone levels was also associated with a loss of vigor among the participants.
Researchers say about 15% of adult workers in the U.S. get five hours or less of sleep per night, and this study suggests this kind of prolonged sleep loss could have a negative consequence on testosterone and men's well-being.