Lack of sleep 'kills a man's sex drive'A study has found that men with poor sleep patterns have significantly lower levels of testosterone, which results in a lack of sex drive.
Experts say that reduced levels of the hormone can bring a host of other negative consequences for young men, including reduced libido and poor reproduction.
They can fail to build enough strength through muscle mass and bone density, leading to low energy levels, poor concentration and fatigue.
Low testosterone levels are also linked to the metabolic syndrome - a cluster of metabolic risk factors that increase the chances of developing heart disease, stroke, and type 2 diabetes.
The study’s findings add weight to growing evidence that sleep deprivation leaves major, long-lasting effects on hormone levels.
Scientists from the University of Chicago found men who get less than five hours sleep a night for a week or longer suffer have far less levels of testosterone than those who get a good night’s rest.
Their study, published in this month's Journal of the American Medical Association (JAMA), found that the levels of the hormone are reduced dramatically to levels more akin to someone 15 years older.
“Low testosterone levels are associated with reduced wellbeing and vigour, which may also occur as a consequence of sleep loss,” said Prof Eve Van Cauter, who led the study.
“As research progresses, low sleep duration and poor sleep quality are increasingly recognised as endocrine disrupters.”
Prof Van Cauter has been studying the effects of sleep deprivation for more than 10 years.
She added: “(A level of ) 15 percent is not an insignificant amount, since it is about the amount that occurs with normal aging by 10 to 15 years."
The study subjected 10 young men, with an average age 24 who were lean and in good health, to a number of “rigorous tests”.
These tests screened for endocrine or psychiatric disorders and sleep problems.
The men then spent three nights in a laboratory sleeping for up to 10 hours. Then over the following eight nights they slept for less than 5 hours.
Researchers took blood samples every 15 to 30 minutes for 24 hours during the last day of the 10-hour sleep phase and the last day of the five-hour sleep phase.
They were also asked to keep a log of how they felt throughout the week.
The study found that testosterone levels were significantly reduced after just one week of sleep deprivation. The men with the lower levels of testosterone reported a decline in their sense of wellbeing and their mood.
Five hours of rest reduced levels of testosterone by between ten and 15 per cent, with the lowest levels recorded in the afternoon between2pm and 10pm.
Prof Van Cauter, who heads the university’s medicine programme, said that, perhaps unsurprisingly, their vigour fell more every day as sleep restrictions were introduced.
Testosterone levels in men decline naturally by between 1 per cent to 2 percent a year as a man ages.
Last year a study found more than three quarters of Britons would rather have a good night’s sleep than indulge in sexual intercourse with their partners.