If you habitually stumble into the office bleary-eyed, grasping a caffeinated beverage like it’s your one and only lifeline, we have bad news for you.
No matter how much extra rest you rack up on your days off, a weekly lie-in is not an adequate fix for nights of lost sleep. Researchers at the University of Colorado, Boulder, have authored a study, now published in Current Biology, with the regrettable conclusion that “catching up” at the weekend will not undo the damage of sleep deprivation during the week. And, perhaps even more frustratingly, attempting to clock in more ZZZs in your spare time can actually make things worse, if you return to your sleep-depriving habits as soon as the next working week starts.
“Our findings suggest that the common behavior of burning the candle during the week and trying to make up for it on the weekend is not an effective health strategy,” Kenneth Wright, director of UC Boulder's Sleep and Chronobiology Lab and senior author of the paper, said in a statement.
It’s common knowledge that going short on sleep is bad for your health. It has been linked to obesity and diabetes. Research suggests it increases cravings, decreases insulin sensitivity, and impairs our ability to regulate sugar. Other studies associate a lack of sleep with depression, neurodegeneration, and Alzheimer’s. It seems even just a night of restless sleep may be enough to affect the genes that control metabolic function.
Past research suggests that sleeping for extra time on the weekend can help the body recover, at least somewhat – but this effect is lamentably short and sweet.
So, to find out how a constant yo-yoing between not enough and too much sleep affects our health, Wright and colleagues recruited 36 healthy adults aged 18 to 39 and monitored their sleep for a grand total of nine nights. The group was divided into three sub-groups – one allowed to sleep for nine hours a night, another for a maximum of five hours a night, and a third that slept no longer than five hours a night for five nights before two nights of sleeping for as long as they liked, followed by two more nights of restricted sleeping.
The team noticed increased snacking, weight gain, and reduced insulin sensitivity in the two recovery groups. The volunteers allowed two days’ worth of lie-ins did show signs of improvement on those days (for example, they snacked less), but any benefits dissipated as soon as the restricted sleeping resumed. What’s more, the lie-in group actually showed worse outcomes on measures like insulin sensitivity at the end of the study. Those whose sleeping was limited to five hours for the whole nine days saw a dip of 13 percent for whole-body insulin sensitivity, whereas those allowed lie-ins saw dips between 9 and 27 percent, with sensitivity in the liver and muscles being particularly low.
"In the end, we didn't see any benefit in any metabolic outcome in the people who got to sleep in on the weekend," said Chris Depner, lead author and assistant research professor of Integrative Physiology.
"It could be that the yo-yoing back and forth – changing the time we eat, changing our circadian clock and then going back to insufficient sleep is uniquely disruptive," added Wright.
Sorry, folks. It seems that when it comes to sleep, consistency is key.