Can You Catch Up on Sleep at the Weekend?

Short nights from Monday to Friday, then a long lie-in on Saturday. Many people run their sleep like a bank account, borrowing during the week and paying it back at the weekend. It seems sensible. The evidence says the account doesn’t balance.

The experiment

In 2019, researchers at the University of Colorado Boulder put 36 healthy young adults through a tightly controlled sleep laboratory study. One group slept normally. A second was allowed only five hours a night. A third had five-hour nights during a working week, then a weekend in which they could sleep as long as they liked, then went back to short nights.

The weekend sleepers did catch some sleep back, but only about an hour in total over the weekend. During that weekend their late-evening snacking fell. Once the short nights started again, the benefits disappeared.

What went wrong

After the weekend, the lie-in group’s body clocks had shifted later. Evening snacking and body weight went back up. And their bodies became worse at handling sugar: insulin sensitivity fell by between 9% and 27%, depending on the measure. As the title of their paper puts it, weekend recovery sleep failed to prevent the metabolic damage of repeated short nights.

The authors suggested that the swing itself may be part of the problem. Sleeping in shifts the body clock, and Monday morning drags it back, a little like flying across time zones every week.

The other side

The picture is not completely bleak. A Swedish study followed 43,880 adults for 13 years. Among those under 65, people who slept five hours or less every night had a 65% higher death rate than those who slept six to seven. But people who slept little on weekdays and long at weekends had about the same death rate as the steady six-to-seven-hour sleepers.

That hints that weekend sleep may make up for something. But the study was observational and relied on people’s own reports of their sleep, so it cannot show cause and effect. Its authors called the compensation idea tentative.

The takeaway

A weekend lie-in may help a little, but it is not a reset button. What the evidence supports most is enough sleep on most nights, at roughly the same times, so there is less debt to repay and less of a weekly jolt to your body clock.