Joy Victory is Deputy Managing Editor of HealthNewsReview.org. She tweets as @thejoyvictory.
For overworked, underslept Americans, Mashable and several other news outlets provided some very tempting clickbait: “Sleeping in on the weekends might prevent an early death.”
The claim stems from a new study examining self-reported patterns of sleep and early mortality. People who reported that they get less than 5 hours of sleep 7 days a week appeared to have the highest rate of death, whereas people who got decent sleep (7 hours or more per night) every night–or made up for it on the weekends–had a lower rate. (But, quite a few people in all the groups died during the study, which stretched 13 years. Turns out none of us are safe from death.)
Via an in-depth questionnaire, researchers asked about 38,000 Swedish people *one time* to self-report how often they slept. Many of the news stories made it sound like this wasn’t the case by saying people “were followed” for 13 years. The only thing researchers tracked for that long was what people died from, and when — not if their sleep patterns changed, which they probably did for a lot of people. (As the parent of a young child who bounces out of bed early no matter the day, I’m sleep deprived a lot. But that won’t last forever…I hope.). This one-time snapshot of self-reported data is an imperfect way to know how much people are really sleeping–though an efficient one, which is why it’s used a lot in these types of studies. To their credit, Mashable did point out this limitation, as did the Washington Post and The Guardian.
The observational study also wasn’t designed to prove that sufficient sleep prolongs life, or the opposite, that sleep deprivation shortens the life span. It was powered to look for correlations, not cause and effect relationships. After controlling for a lot of things, like tobacco use, general health status, shift work, alcohol intake, caffeine intake, and so on, the patterns still held together enough to point to some sort of relationship between sleep and mortality rates.
But it’s still got a chicken-or-the-egg problem: Are people dying early because lack of sleep made them more prone to illnesses like cancer and heart disease? Or did underlying illness make them prone to not sleeping enough? Or is there another altogether different factor at play besides sleep that wasn’t captured by the survey? We can’t know, which is why headline writers must be very careful not to over-step the evidence and make it sound conclusive.
Perhaps I’m just tired–and what working parent of a preschooler isn’t–but for now, there’s too many unclear answers for me to freak out that I won’t get to sleep in this weekend. Or next weekend. Or the weekend after that…