Many of us have stayed up late studying for finals, working overtime, or watching cartoons until the wee hours thinking we could catch up on all that lost sleep over the weekend. Research published Thursday in Current Biology, however, suggests that missing out on sleep during the week comes with negative health consequences that persist — even if you manage to sleep through the whole weekend.

In the small study, Colorado researchers demonstrate that getting only five hours of sleep each night is associated with health consequences like eating more after dinner, weight gain, the delayed release of the sleep-linked hormone melatonin, and reduced whole-body insulin sensitivity. More importantly, these effects don’t go away after a weekend of sleeping as much as you want if your unhealthy sleep patterns resume after the weekend.

“For participants in the weekend recovery (WR) group, ad libitum weekend recovery sleep failed to prevent any of these metabolic derangements when assessed during recurrent insufficient sleep following the weekend,” write the researchers, led by first author Christopher Depner, Ph.D., an assistant research professor of integrative physiology at the University of Colorado Boulder.

Watching 'Rick and Morty' until 2 AM on a work night? You might not be able to make up for it over the weekend. Unsplash / @Matthew_T_Rader

Weekend Sleep Doesn’t Make a Difference

The 36 participants involved in the study were split into three groups: The control group (eight people) got a solid nine hours each night, while the two experimental groups (14 people each) slept five hours.

After five nights of insufficient sleep, one of the experimental groups got the chance to recover with ad libitum sleep for two nights, while the other group got no recovery time. In both groups that got insufficient sleep, participants experienced weight gain, more after-dinner eating, disrupted circadian rhythm, and insulin insensitivity. These effects showed up regardless of whether the participants got the chance to catch up on sleep over the weekend.

Serious Health Consequences

Most of the health consequences they observed are commonly associated with disrupted sleep, but eating more after dinner might sound a little strange. The researchers explain that consuming more calories at the wrong time of day is associated with metabolic disruption, and so the fact that the sleep-deprived group ate almost 500 more calories after dinner than the well-rested group suggests that insufficient sleep messes with multiple pathways associated with metabolism.

These results build on a growing body of scientific research that proves what your parents have always nagged you about: getting enough sleep is really important.

A similar 2018 study in Scientific Reports showed that people who get sufficient sleep tend to have better heart and metabolic health, while people who didn’t get enough sleep exhibit a host of health risk factors, like higher weight, greater risk of heart attack or stroke, higher blood pressure, and higher blood sugar. The new study shows the same results, but it adds a key detail: Catching up on sleep on weekends won’t heal these health problems if you just go back to missing out on sleep on Monday night.

More sleep science stories:

Abstract: People commonly increase sleep duration on the weekend to recover from sleep loss incurred during the workweek. Whether ad libitum weekend recovery sleep prevents metabolic dysregulation caused by recurrent insufficient sleep is unknown. Here, we assessed sleep, circadian timing, energy intake, weight gain, and insulin sensitivity during sustained insufficient sleep (9 nights) and during recurrent insufficient sleep following ad libitum weekend recovery sleep. Healthy, young adults were randomly assigned to one of three groups: (1) control (CON; 9-h sleep opportunities, n = 8), (2) sleep restriction without weekend recovery sleep (SR; 5-h sleep opportunities, n = 14), and (3) sleep restriction with weekend recovery sleep (WR; insufficient sleep for 5-day workweek, then 2 days of weekend recovery, then 2 nights of insufficient sleep, n = 14). For SR and WR groups, insufficient sleep increased after-dinner energy intake and body weight versus baseline. During ad libitum weekend recovery sleep, participants cumulatively slept 1.1 h more than baseline, and after-dinner energy intake decreased versus insufficient sleep. However, during recurrent insufficient sleep following the weekend, the circadian phase was delayed, and after-dinner energy intake and body weight increased versus baseline. In SR, whole-body insulin sensitivity decreased 13% during insufficient sleep versus baseline, and in WR, whole-body, hepatic, and muscle insulin sensitivity decreased 9%–27% during recurrent insufficient sleep versus baseline. Furthermore, during the weekend, total sleep duration was lower in women versus men, and energy intake decreased to baseline levels in women but not in men. Our findings suggest that weekend recovery sleep is not an effective strategy to prevent metabolic dysregulation associated with recurrent insufficient sleep