Bad news if you are waiting for the weekend to catch up on sleep – new research shows that a relaxing Sunday lie-in won’t fix the metabolic damage caused by sleep deprivation during the week.
The study has found that poor sleep during the week led to more snacking after dinner, weight gain, a delay in circadian rhythm and lower insulin sensitivity – which is a risk factor for type 2 diabetes.
Unfortunately, sleeping in over the weekend “was not sufficient to mitigate the negative consequences that we see during sleep loss”, says study author Christopher Depner at the University of Colorado, Boulder.
Obesity and diabetes are becoming major health crises, and a growing body of research now links poor sleep to such metabolic problems. While sleep experts recommend at least 7 hours per night, as many as one in three adults in the US may be falling short.
To test whether sleeping in over the weekend could offset this metabolic damage, Depner and his colleagues randomly assigned 36 healthy young adults to one of three groups. The control group was allowed to sleep for 9 hours each night, while those in the sleep-deprivation group were limited to only 5 hours per night over the nine-day study period.
A third group was restricted to 5 hours of sleep during the weekdays but could sleep as much as they wanted at the weekend. After this, they returned to another two nights of only 5 hours.
Sleep deprivation led participants to snack more after dinner, but Depner found that the amount of snacking dropped off after a weekend sleep-in. Once participants had their sleep restricted again, however, the researchers noticed that not only did they begin to snack more after dinner again, their body weight increased and their circadian body clock was thrown off balance.
At the end of the experiment, insulin sensitivity for the liver and muscles of the participants who were allowed to sleep in at the weekend was actually more impaired than it was in those who were constantly sleep-deprived.