Experts have been recommending seven to eight hours of uninterrupted sleep each night since the beginning of time (at least, your lifetime), but a new theory suggests this may not be the way we were designed to sleep. Proponents of "segmented sleep" say that our earliest ancestors snoozed whenever they felt like it—which usually meant several two-hour naps throughout the day.
Does it work? "Having three little kids, twins included, I’m familiar with sleeping in chunks, and it is better than nothing," Dr. Lopez says. "But it's better to sleep seven to eight hours at one time so you can go through the various sleep cycles because each has a specific purpose. During each phase, your body releases lots of hormones, natural killer cells, etc. to help repair and restore the body."
Is it safe? It's not exactly dangerous, but that doesn't mean it's a good idea. "Studies have shown over and over again that any type of disrupted or 'short' sleep (anything less than seven hours per night) increases levels of cortisol (your stress hormone), leading to insulin interference, blood sugar instability, and then food cravings (especially for high-sugar comfort foods)," Dr. Talbott says. All of this can lead to weight gain—predominantly belly fat. "Getting adequate sleep is every bit as important as proper diet and regular exercise for maintaining a healthy weight," he says.
Final verdict: Deny it, unless this is how you naturally sleep already.