Study: To live longer, sleep in on weekends

Sleeping in on a day off feels marvelous, especially for those of us who don’t get nearly enough rest during the workweek. But are the extra weekend winks worth it? It’s a question that psychologist Torbjorn Akerstedt, director of the Stress Research Institute at Stockholm University, and his colleagues tried to answer in a study published Wednesday in the Journal of Sleep Research.

Akerstedt and his colleagues tracked more than 38,000 people in Sweden over 13 years, with a focus on their weekend vs. weekday sleeping habits. This peek at weekend slumber fills in an “overlooked” gap in sleep science, Akerstedt said.

Previous sleep studies asked people to count their hours of sleep for an average night, without distinguishing between workdays and days off. Not in the new study. People under the age of 65 who slept for five hours or less every night, all week, did not live as long as those who consistently slept seven hours a night.

But weekend snoozers lived just as long as the well-slept. People who slept for fewer than the recommended seven hours each weekday, but caught an extra hour or two on weekends, lived just as long as people who always slept seven hours, the authors reported.

“It seems that weekend compensation is good” for the sleep-needy, Akerstedt said, though he cautioned that this was a “tentative conclusion” of this new research. Epidemiologists who spoke with the

Washington Post described the result as a plausible finding, if not a statistically robust one, that deserves more investigation.

Michael Grandner, director of the Sleep and Health Research Program at the University of Arizona’s College of Medicine, who was not involved with this work, warned that sleep is not like a financial transaction. We can’t deposit zzzs over the weekend and expect to cash them out later.

A superior metaphor, he said, is a diet. For the sleep-deprived, sleeping in on a weekend is like eating a salad after a series of hamburger dinners — healthier, sure, but from “one perspective the damage is done.”

In September 1997, thousands and thousands of Swedes filled out 36-page health questionnaires as part of a fundraiser for the Swedish Cancer Society. The study’s authors followed 38,015 survey participants over 13 years to track their mortality rates.

Between 1997 and 2010, 3,234 of these subjects died, most as a result of cancer or heart disease. That’s roughly six deaths per 1,000 people per year. By comparison, the world mortality rate in 2010 was nearly eight in 1,000.

Epidemiologist and cardiovascular doctor Franco Cappuccio at the University of Warwick in England, also not a member of the research team, said that the study “looks good” but that the authors missed a trick: “a full explanation of the possibility of daytime napping.” The researchers only asked if people took daily naps, but did not quantify nap length. “Therefore the adjustments may not be effective,” Cappuccio said.

Grandner urged the overworked and underslept not to view sleep as time lost. “We live in a society that considers sleep unproductive. What’s more un-American than unproductive time?” That’s not a healthy approach — as our bodies are built to consume food and water, he pointed out, we are also built to sleep.