Banking more sleep on the weekend might help ease health problems associated with not getting enough during the week, and even reduce the risk of an early death, according to the latest research.
The study of more than 38,000 adults showed a higher mortality rate among young and middle-aged adults who slept for less than five hours a night – but when it came to those who caught up on that lack of sleep over the weekend, the mortality rate difference disappeared.
This is a long way from proving that extra weekend sleep can counteract the hit our bodies take by not getting enough slumber – but one of the team, Torbjörn Åkerstedt from Stockholm University in Sweden, says it opens up some interesting possibilities.
"The assumption in this is that weekend sleep is a catch-up sleep," Åkerstedt told Nicola Davis at The Guardian – though for now that's just a working hypothesis.
While we've seen plenty of studies looking at the relationship between sleep and our health, the different balance between weekday and weekend sleep isn't often taken into account, which is where the researchers behind the new study wanted to focus.
Self-reported data on a total of 38,015 people was used, and participants listed the sleep they got during working days and days off, which for the sake of simplicity was referred to as 'weekdays' and 'weekends' for the analysis.
The team also used statistical models to factor out influences such as gender, body mass index, physical activity, alcohol consumption, and whether or not someone was a smoker.
The light sleepers in the sample aged under 65 – those who slept for less than five hours a night in the week and at weekends – had a 65 percent higher mortality rate than the reference group who got six or seven hours a night, the study found.
That's based on following death records over the course of 13 years, though it's important to note that sleep behaviour was only measured once at the start of that period.
However, "the mortality rate of individuals with short sleep during weekdays, but medium or long sleep over weekends, did not differ from the reference group rate", report the researchers.
That shift in mortality rates also disappeared for people over the age of 65 – maybe because they're more able to get the sleep they need, the researchers say. In that older age bracket, no link was shown between sleep duration and mortality.
Here's another interesting finding: those who slept for more than nine hours a night also had a higher mortality rate than the reference group. That's possibly because more time in bed relates to other underlying health problems, according to the study authors.
With a reasonably sized sample, and a sharp difference in early death rates for those who don't catch up on their sleep on the weekends, the research is worth making note of.
As we've mentioned though, the study didn't track sleeping changes over time, and may not be representative of the population at large – fewer of the participants were smokers than you would usually expect, for example, possibly because the surveys were originally done at a cancer charity event.
Other experts have said the study is a useful one, but that more research is needed before we can fully know how weekend sleep can make up for a weekday deficit.
Michael Grandner from the University of Arizona, who wasn't involved in this particular study, warned against relying on the weekend to recover a sleep deficit. He told Ben Guarino at The Washington Post that it might be more like eating a salad after several hamburgers – definitely healthier, but not able to reverse all the negative effects.
As ever, the best advice is to find out how much sleep you need (experts recommend between seven and nine hours a night), and stick to it. If you are running low on sleep though, it just might be possible to use your days off to redress the balance in some way.
The research has been published in the Journal of Sleep Research.