Science explains why you wake up at 3 a.m., and how to go back to sleep
About one in five people have middle-of-the-night insomnia. What should you do if you wake up in the middle of the night and can’t fall back asleep? This is one of the most common—and frustrating—forms of insomnia. It turns out there’s a biological reason for it. And there are things you can do tha...