A sleep study revealed that less than six hours of sleep a day can limit the brain's ability to function properly.
The study, published on Monday in the journal Proceedings of the National Academy of Sciences, found that people experiencing less than six hours of sleep were five times as likely to suffer from attention lapses, delayed reaction times and decreased vigilance.
"If somebody is routinely awake for more than 18 hours daily, then they are also routinely sleeping for less than six hours daily. Therefore, it was unknown whether any decline in vigilance or other functions was due to the extended wakefulness or restricted sleep," senior author Elizabeth B. Klerman said of the study
The study involved 17 participants. Nine were forced to stay awake for 15.33 hours while only allowed 4.67 hours of sleep in a 20-hour "day." These periods lasted for 32 days, Medical Express reported.
Then a control group of eight participants stayed awake for 13.33 hours and slept for 6.67 in that 20-hour day — the equivalent of sleeping 8 hours.
From there researchers performed tests on the participants to study their reaction times. The impaired participants didn't even notice they were impaired from the lack of sleep, Medical Express reported. And as the lack of sleep continued, the test results worsened over the 32-day period.
"We have shown that sleep in itself is important," Klerman said, according to Medical Express. "People cannot learn to live on insufficient sleep and they may not be aware of their reduced cognitive abilities. More so, our study suggests the importance of longer episodes of sleep, rather than a 'split sleep' schedule, though further evidence would be needed to test this directly."
There may be hope, however, for people suffering from a chronic lack of sleep. In a separate study published Tuesday in the Journal of Sleep Research, it may be possible to "catch up" on those missed hours on weekends.
The study examined 38,000 adults and found there was a 65 percent higher mortality rate for people who got less than 5 hours of sleep during the week and continued that habit into the weekend.
"The results imply that short (weekday) sleep is not a risk factor for mortality if it is combined with a medium or long weekend sleep," the authors wrote in the paper, according to Medical Express. "This suggests that short weekday sleep may be compensated for during the weekend, and that this has implications for mortality."