After a working week of sleepless nights many of us think that a long lie in on Saturday morning will help rejuvenate our ailing bodies.
However, scientists today claimed that trying to catch up on the shut-eye we lose during the week may be a fruitless task.
Researchers have found that the effects of restricted sleep – four hours or less a night – are cumulative and that having very little sleep is almost as bad for the body as no sleep at all.
Even catching less sleep for just a few days affects the way the mind functions, and a single night’s decent sleep may not immediately reverse this, say researchers from the University of Wisconsin-Madison.
Lead researcher Dr Chiara Cirelli said: ‘There’s a huge amount of interest in sleep restriction in the field today.
‘Instead of going to bed when they are tired, like they should, people watch TV and want to have an active social life,.
‘People count on catching up on their sleep on the weekends, but it may not be enough. Even relatively mild sleep restriction for several nights can affect an individual’s ability to perform cognitive tasks.
‘For instance, recent studies in humans have shown that five days with only four hours of sleep each night result in cumulative deficits in vigilance and cognition, and these deficits do not fully recover after one night of sleep, even if ten hours in bed are allowed.’
She added that insomnia can also increase the bodies resistance to insulin and lead to diabetes.
Dr Cirelli’s team studied the affect of sleep deprivation on rats and recorded their slow wave activity (SWA) when they were asleep and awake. SWA indicates when an individual needs to sleep because the longer someone stays awake, the higher their SWA level.
The scientists found that SWA accumulated over time, even when the rats were able to snatch short periods of rest.
Dr Cirelli explained: ‘Monitoring SWA levels during waking time is very important in understanding the whole picture.
‘High SWA levels during periods of both sleeping and waking signal that you need to go to sleep.’
Researchers, whose work is published in Proceedings of the National Academy of Sciences, hope that the study will help scientists better understand the harmful effects of sleep disturbance.