Sleep deprivation is epidemic in modern society, and indeed is the most frequent symptom we see in our practice. There is now evidence that impaired sleep lowers testosterone production. (JAMA, June 1, 2011, pp 2173-2174.)
Ten healthy young men spent 11 days in the laboratory getting 10 hours of sleep, followed by eight nights of sleep restricted to 5 hours nightly. By the end of the study, daytime testosterone levels decreased by 10-15%. Cortisol levels were not affected.
In men, testosterone levels generally decline by 1-2% per year. Low levels affect sexual desire and behavior, and indicate reduced fertility. Nearly half of the inability to conceive occurs subsequent to male reproductive defects. Testosterone deficiency also leads to reduced muscle mass and strength, weight gain, lower bone density, and impaired vigor and well-being.
It is important, therefore, that evaluations of reduced testosterone levels should also focus on sleep quality and habits. Enhanced sleep may raise testosterone levels.
Allan Sosin MD