One in five Americans has lost interest in sex -- and not because they have a headache, a study released Monday showed.
The culprit for the loss of libido is lack of sleep due to excessively long work hours and too much overtime, according to a study by the National Sleep Foundation (NSF).
"Longer work days and more access to the workplace through the Internet and other technology appear to be causing Americans to get less sleep," said Darrel Drobnich, head of the NSF, in a statement.
"Nearly 50 million Americans chronically suffer from sleep problems and disorders that affect their careers, their personal relationships and safety on the roads," Drobnich said.
The study showed that more than one-third of Americans -- 36 percent -- have fallen asleep at the wheel, and nearly two-thirds report having sleep problems, such as waking at night or difficulty falling asleep.
Americans sleep on average six hours and 40 minutes a night, or less than the seven hours, 18 minutes they said they needed, the study showed.
"Studies show that habitually getting inadequate sleep -- less than seven or eight hours each night -- creates long-lasting changes to one's ability to think and function well during the day," said Thomas Balkin, the deputy head of the NSF.
One reason many Americans aren't getting enough sleep is because the amount of time they spend at work or commuting is so great.
One third of Americans work 10 hours a day or longer, and one in five spend another 10 hours working from home, the study showed.
The average commute time is more than three-quarters of an hour, it showed.
Shift-workers, who are predominantly male (70 percent), fare even worse than most: one-third said they sleep less than six hours a night on workdays, 48 percent have driven while drowsy, and one in four said lack of sleep has affected their sex life.
"The impact of not getting good sleep is far-reaching and has Americans compromising their productivity, safety, health and relationships," said Drobnich.
One thousand American adults were surveyed for the poll on sleep by the NSF.