Sleep debt persists despite sleeping in late on weekends

By Dr. Liji Thomas, MDMar 1 2019

Many people go without sleep for days, and think they can make it up by waking late on the weekend. However, this just makes things worse, according to a new study at the University of Colorado Boulder.  

Shutterstock | Siriluk ok

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 the Sleep and Chronobiology Lab

Other studies showed an increased risk of diabetes and obesity with too little sleep. This might be because people staying up late tend to snack more at night, while the body responds less readily to insulin. Another cause might be that the body cannot control its blood sugar concentrations as well without enough sleep. Impairment of health is seen after losing sleep for just one night, according to recent studies at the CU Boulder.

Of course, researchers also found that sleeping in on weekends does help with some degree of recovery, but only for a short time.

If so, what would be the result of yo-yo-ing between too little sleep during the week and prolonged sleep on weekends? Wright and Chris Depner joined forces to find out.

Their current study included 36 adults in good health, between ages 18 and 39, who lived in a laboratory for two weeks, so that researchers could keep tabs on their diet, the amount of light they were exposed to, and their sleep.

Following initial testing for baseline results, three groups were formed. In Group 1, they could sleep for nine hours every night, for nine nights. Group 2 participants slept only five hours a night for the same duration. Group 3 slept five hours every night for five days, slept in over the weekend for as long as they felt like, and then again went back to their five hours of sleep for the next two days.

The results showed that night snacking, weight gain and reduced sensitivity to insulin were all higher in groups 2 and 3. However, some indices in group 3 showed modest improvement on the sleeping-in weekends; there was less night snacking, which disappeared once they returned to their lack-of-sleep routine.

In short, there was no lasting metabolic improvement with sleeping-in over the weekend.

Indeed, some health risks actually went up in this group. There was a 13 percent decrease in whole body insulin sensitivity with continuing lack of sleep, compared to a decline by 9 – 27 percent decline in those who tried to make up their sleep over the weekend. This loss of sensitivity was greatest in the muscle and liver tissue.

Wright suggested that this could be due to disruption of the circadian rhythms, or body activity cycle, by repeated fluctuations in factors such as meal timings, changes in the body clock, and sleep duration.

Another observation showed that loss of sleep is difficult to make good. On Friday and Saturday, people who slept in enjoyed the extra sleep, but on Sunday they could not fall asleep on time, because of a change in their body clock.

The overall gain from sleeping in was only about an hour, on average. This was slightly more for men than for women.

The takeaway? Sleep for at least seven hours a night as consistently as you can.

Michael Twery, director of the National Center on Sleep Disorders Research (NCSDR), says, “This study demonstrates the importance of getting sufficient sleep on a regular schedule. Frequently changing sleep schedules is a form of stress associated with metabolic abnormalities.”

The study was published today in Current Biology.