After a full week of getting up early and losing sleep, many people try to catch up on the weekends. But can we ever truly catch up on insufficient sleep?
In a new study, researchers investigated whether extra weekend sleep is enough to reduce some of the metabolic risks associated with poor sleep and untreated sleep disorders, including obesity and diabetes. The findings show that extra weekend sleep does not reverse these risks, and in some cases, it even appears to make things worse.
“The key take-home message from this study is that ad libitum weekend recovery or catch-up sleep does not appear to be an effective countermeasure strategy to reverse sleep loss induced disruptions of metabolism,” said Dr. Kenneth Wright of the University of Colorado Boulder.
For the study, healthy young adults were randomly assigned to one of three groups. The first group was given plenty of time to sleep (9 hours) each night for 9 nights. The second had just 5 hours to sleep each night over that same period. The third group slept 5 hours for 5 days followed by a weekend in which they slept as much as they liked before returning to another 2 days of restricted sleep.
In the two sleep-restricted groups, insufficient sleep led to an increase in snacking after dinner and weight gain. During the weekend recovery sleep in the third group, participants slept an hour longer on average than they usually would. They also consumed fewer extra calories after dinner than those who got insufficient sleep.
However, when they went back to getting poor sleep after the weekend, their circadian body clock was timed later. They also ate more after dinner as their weight continued to rise.
The findings show that sleep restriction in the first group was linked to a decrease in insulin sensitivity of about 13 percent. But the group that was given a chance to sleep more on the weekend still showed less sensitivity to insulin. The insulin sensitivity of their whole bodies, liver, and muscle decreased by 9 to 27 percent after they got insufficient sleep again, once the weekend was over.
“Our findings show that muscle- and liver-specific insulin sensitivity were worse in subjects who had weekend recovery sleep,” said researcher Dr. Christopher Depner, noting that those metabolic deviations weren’t seen in the people who got less sleep all along.
“This finding was not anticipated and further shows that weekend recovery sleep is not likely [to be] an effective sleep-loss countermeasure regarding metabolic health when sleep loss is chronic.”
Wright says it’s still unclear whether weekend recovery sleep can be an effective health strategy for people who get too little sleep only occasionally; for example, only a night or two per week. They hope to investigate the fine details of these dynamics in future studies, including the influence of daytime napping and other strategies for getting more sleep.
The Sleep Research Society and American Academy of Sleep Medicine recommends 7 or more hours of sleep nightly for adults, to promote optimal health.
The findings are published in the journal Current Biology.
Source: Cell Press