Can you catch up on lost sleep on the weekend?

5 min read

On weekdays I only get five hours. To make up for it, I sleep until noon on Saturday and Sunday.

You often hear that "catch-up sleep is pointless." But looking at the research, there isn't just one answer. The answer changes depending on what you measure.

Measured by lifespan, weekend sleep "made up" for it

A study in Sweden followed more than 43,000 adults for up to 13 years [1].

Among people under 65, those who slept five hours or less every day had a higher risk of death than those who slept six to seven hours every day. But among people who slept five hours or less on weekdays and slept longer on weekends, the risk of death wasn't higher. In people 65 and over, no link between sleep duration and mortality was found at all.

But this was an observational study with self-reported sleep. People who can sleep long on weekends may differ in other ways, such as having more slack in their lives.

Measured by metabolism, weekend sleep didn't restore it

An experiment in the United States, on the other hand, gave a different result [2].

Participants were split into a group that slept enough, a group whose sleep was kept short throughout, and a group with short sleep on weekdays and as much as they wanted on weekends, and their metabolic changes were measured. In the group whose sleep stayed short, insulin sensitivity fell by about 13%. And even the group that slept as much as they liked on weekends didn't avoid the drop in insulin sensitivity. In muscle and liver, insulin sensitivity was actually worse than in the other groups.

This was a small, short experiment. Even so, it shows that when sleep loss continues, weekend catch-up sleep isn't a way to protect your metabolism. I wrote about blood sugar and insulin in "Why does blood sugar matter so much for health?"

Do the two studies contradict each other?

At first glance, they seem to say opposite things. But the two studies are measuring different things.

So we can't say flatly either "catch-up sleep is pointless" or "you can make it all back." What we can say is that catch-up sleep may be "better than nothing," but it doesn't erase all the effects of sleep loss.

The side effect: your body clock shifts

Sleep late on weekends and your wake time shifts far from your weekday one. The mismatch in sleep timing between workdays and days off is called "social jet lag" [3]. It's like flying to a country in a different time zone and back every weekend.

Sleep until noon on your day off, and you can't sleep on Sunday night, and Monday morning is hard. That shift may also be part of the Sunday-night weight I wrote about in "Why are Sunday nights so heavy?"

The official guide: six hours or more for adults

Japan's Ministry of Health, Labour and Welfare's "Sleep Guide for Health Promotion 2023" says that the right amount of sleep varies between individuals, and gives six hours or more as a guide for adults. It also recommends paying attention not only to duration but to whether you feel rested when you wake up. For older adults, it recommends not spending eight hours or more in bed [4].

Summary: keep it steady rather than catching up

• In a study tracking mortality, people who slept longer on weekends didn't show the higher death risk linked to weekday sleep loss (observational study)
• In an experiment measuring metabolism, weekend catch-up sleep didn't prevent the drop in insulin sensitivity
• Catch-up sleep shifts your sleep timing between weekdays and days off (social jet lag)
• Six hours or more is the guide for adults (Sleep Guide 2023, Japan)

Rather than making up for weekday loss on the weekend, add even a little sleep on weekdays, and keep your wake time as steady as you can on days off too. If you really need more sleep on the weekend, going to bed earlier seems to shift your body clock less than sleeping until noon.

Once you've made time to sleep, it's also worth cutting noise and light in the bedroom. I put together how to choose earplugs and eye masks in "How to choose earplugs and an eye mask."