Do you sleep in on the weekends like your life depends on it? It actually might.
People who average about five hours of sleep during the week have a higher mortality risk rate than those who get an average of seven, according to a study published in the Journal of Sleep Research, but the damage can be counteracted with a nice snooze on your days off.
Researchers examined data from nearly 44,000 people who took part in a 1997 Swedish medical survey — and then tracked how many died within the next 13 years. They found that those people who received no more than five hours of sleep during the week but then managed to get at least nine hours of rest during the weekend actually had no increased risk of an early death.
Torbjörn Åkerstedt, an author of the study, said that his study doesn't contradict the growing body of scientific evidence that lack of sleep can lead to a person's early demise, according to Mashable. Instead, the clinical neuroscience professor from the Karolinska Institute in Sweden said his research helps fill in some gaps in other studies.
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He said his team "suspected" that studies that didn't look at catching up on sleep during weekends "may not be enough."
"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 study reads. "This suggests that short weekday sleep may be compensated for during the weekend, and that this has implications for mortality."
He told Popular Science that his study is important because "previous work hasn't considered weekend sleep."
There are some caveats, however. The findings do not apply for people over the age of 65, the study says, and the Swedish survey only once asked subjects to quantify how much sleep they average throughout the week. Also, too much sleep can be a problem, the study says, because those who get over eight hours of sleep every day of the week actually have a higher mortality risk than those who just average between six to seven hours.
Jennifer Roxanne Prichard, neuroscientist from the University of St. Thomas, said the study, while a "helpful piece of information," doesn't look at a person's quality of life. A study of Korean adolescents found that those who sleep in on the weekends to make up for a busy week actually have a higher risk of self-injury and suicidal thoughts, as noted by Popular Science, while current research also indicates that you can't make up for the cognitive decline brought on by nights with little shut-eye.
And Michael Grandner, who heads the University of Arizona's Sleep and Health Research Program, told The Washington Post that it's wrong to believe a long sleep on the weekend can completely make up for a restless week. He compared it to gobbling down a lot of hamburgers and then sticking strictly to salads.
Despite those potential issues, "body clock" researcher Stuart Peterson told The Guardian that the study adds much needed context.
“It fits with what we do know about sleep," he said. "That sleep is regulated by the body clock but also regulated by what is called a homeostatic process, which means the longer you are awake the more you need to sleep.”