Researchers at Northwestern University have discovered that when animals are partially sleep deprived over consecutive days they no longer attempt to catch up on sleep, despite an accumulating sleep deficit. The study finds that repeated partial sleep loss negatively affects an animals ability to compensate for lost sleep and that the body responds differently to chronic sleep loss than it does to acute sleep loss.
The results, which shed light on a problem prevalent in industrialized nations with 24/7 societies such as the United States, where Americans get nearly an hour less sleep a night than they did 40 years ago, were published online recently by the Proceedings of the National Academy of Sciences (PNAS).
We now know that chronic lack of sleep has an effect on how an animal sleeps, said Fred W. Turek, professor of neurobiology and physiology and director of Northwesterns Center for Sleep and Circadian Biology and an author of the paper. The animals are getting by on less sleep but they do not try and catch up. The ability to compensate for lost sleep is itself lost, which is damaging both physically and mentally.
The findings support what other scientists have discovered in recent experimental studies in humans. Chronic partial sleep loss of even two to three hours per night was found to have detrimental effects on the body, leading to impairments in cognitive performance, as well as cardiovascular, immune and endocrine functions. Sleep-restricted people also reported not feeling sleepy even though their performance on tasks declined.