Everyone likes a cheeky lie-in now and again on a weekend, but it comes with the annoying side-effect of guilt. Shouldn’t you be out doing more with your weekend?
Well, we’ve got good news. In a study published in the Journal of Sleep Research, Swedish researchers found that having a lie-in could actually lower your mortality rate, if you’d been missing out on sleep during the week.
Previous research has found that adults under the age of 65 who sleep less than five hours each night of the week had a higher risk of death. But this study suggested that catching up on sleep over the weekend could alleviate that risk.
"The results imply that short (weekday) sleep is not a risk factor for mortality if it is combined with a medium or long weekend sleep," the researchers, led by Torbjörn Åkerstedt from Stockholm University, wrote in their paper.
"This suggests that short weekday sleep may be compensated for during the weekend, and that this has implications for mortality."
In the study data from 38,000 adults was used from a lifestyle and medical survey in 1997, whose fates were followed up in 2010 on a national death register. Previous studies had only looked at the link between sleep duration during the week and mortality from the survey.
Those results showed that people under the age of 65 who slept less than five hours a night for seven days a week had a 52 percent higher mortality rate than those getting six or seven hours. However, this new study found that if the former group then slept for eight hours or more on the weekend, there was no increase.
Don’t sleep too much, however. Because the researchers also saw that sleeping for eight hours or more every day of the week resulted in a 25 percent higher mortality rate compared to those with six or seven hours a day.
There were a few limitations from the study. For one thing, sleep duration was self-reported by participants. It was also only assessed on one occasion, so the researchers could not see changes over time.
“The use of repeated measurements through follow-up questionnaires would have helped keeping track of sleep habits changes,” they noted in their paper.
Still, the results are interesting. Stuart Peirson, an expert in the human body clock who was not involved in the research, told The Guardian it “fits with what we do know about sleep,” offering a more nuanced view on how much sleep we need to get.