By Dianna Douglas
More research practically begging people to get a good night’s sleep has come out of the sleep labs at the University of Chicago. Eve Van Cauter and Rachel Leproult have discovered that a week of inadequate sleep means less testosterone in young men.
A lot less.
In the study, ten healthy young men gave blood samples after a week of sleeping just five hours a night. By the end of the week, they had 15 percent less testosterone than normal. “This is not an insignificant amount, since it is about the amount that occurs with normal aging by 10 to 15 years,” Van Cauter said. As a man ages, testosterone production decreases by 1 to 2 percent a year.
The lack of testosterone affected not only the reproductive function of these young men, but their happiness as well. Testosterone is a vital hormone for a man’s physical and mental health, and is released into the body during sleep.
“Low testosterone levels are associated with reduced well being and vigor,” Van Cauter said, explaining why the young men said they felt grumpy and lethargic, and their mood worsened as the study progressed.
Low testosterone is associated with low energy, reduced libido, and poor concentration. Consumer Reports Health found in a recent survey that feeling too tired is the reason men cite most often for a low sex drive.
This isn’t just a lab exercise – sleep loss is endemic in modern society. At least 15 percent of the adults in the US get less than 5 hours of sleep a night. Shift workers are especially at risk for lost sleep. The average American got nine hours of sleep in 1910 and got seven in 1975. The cumulative effects of short sleep are still being discovered, and they’re all bad. People who don’t get enough sleep are fatter, more likely to have diabetes, have all sorts of learning and cognitive problems, and die earlier. Van Cauter says that a nation that doesn’t sleep enough has an epidemic of obesity and diabetes.
“As research progresses, low sleep duration and poor sleep quality are increasingly recognized as endocrine disruptors,” Van Cauter said. Mess with the delivery of hormones throughout the body, and people become hungrier and sadder. Their blood pressure goes up and their insulin production goes haywire.
Previous research from the sleep labs has shown that there are other ways in which poor sleep is like premature aging. A study from 1999 showed that chronic poor sleep interrupted glucose tolerance and endocrine function in the same way as diabetes and old age. “Chronic sleep loss may hasten the onset and increase the severity of age-related ailments such as diabetes, hypertension, obesity and memory loss,” Van Cauter said at the time. Some patients had a glucose tolerance level comparable to people with type-2 diabetes after less than a week of poor sleep.
The study about testosterone and sleep deprivation was published in the Journal of the American Medical Association on June 1. The authors suggested that the next step in the research is to see if helping men sleep better is a good way to treat testosterone deficiency.
Leproult R, & Van Cauter E (2011). Effect of 1 week of sleep restriction on testosterone levels in young healthy men. JAMA : the journal of the American Medical Association, 305 (21), 2173-4 PMID: 21632481