Why would you ever wake up earlier than you need to on a Saturday? Here’s one reason: Sleeping in on the weekends can increase your weight and disease risk. Social jetlag-or the difference in your sleeping patterns between days you work and wake up with an alarm and days you have off and sleep according to your natural clock-may increase your risk for obesity-related diseases. (Sleeping in because of exhaustion? Read about 6 Surprising Things That Make You Tired.)
Past German research has found that the more severe your social jetlag, the more likely you are to be overweight. And researchers from the Medical Research Council in the UK have now linked sleeping in with an increased risk of heart disease, type 2 diabetes, cancer, and early death, according to a new study in the journal Obesity.
And that’s just from a two-hour difference. That’s right: If you normally rise at 6 a.m. but naturally wakeup at 8 a.m. on the weekends, your waistline and overall health may be at risk. And the larger that time gap becomes (or, the longer you sleep in or earlier you’re forced to wake up), the higher your risk. (Find out more: Why Sleep Is the No. 1 Most Important Thing for a Better Body.)
Unfortunately, researchers don’t know why exactly this happens, but both research teams speculate that social jetlag interrupts healthy habits like diet and exercise. “As a result of this social jetlag, people are chronically sleep-deprived. They are also more likely to smoke and drink more alcohol and caffeine,” said Till Roenneberg, author of the older German study and professor at the University of Munich. (What Really Happens When You’re Sleep Deprived?)
So, how do you counteract it? "Waking up with an alarm clock is a relatively new facet of our lives," Roenneberg said. "It simply means that we haven't slept enough and this is the reason why we are chronically tired." Try and keep your sleep schedule as close to your body's natural clock seven days a week to avoid exhaustion and weight gain. Now that's what we call beauty sleep.
