(Newser) – It's important to get a good night's sleep for lots of reasons: mood, proper cognitive functioning, and, this just in, sex. A study from the University of Chicago suggests that men who don't routinely grab quality shut-eye have less of a desire to do other things in the bedroom, the Telegraph reports. Specifically, men who get less than 5 hours' sleep a night for a week suffer a significant drop in testosterone: A sleep-deprived 25-year-old might have levels more common in a 40-year-old.

“Low testosterone levels are associated with reduced wellbeing and vigor, which may also occur as a consequence of sleep loss,” says the lead researcher. “As research progresses, low sleep duration and poor sleep quality are increasingly recognized as endocrine disrupters.” (Read more sleep deprivation stories.)

