11 Reasons You Wake Up At Night

Getting older

Everyone has a biological clock that determines when they get tired at night and when their body wakes up in the morning. But starting around age 40, your clock begins to shift. Researchers aren’t sure exactly why this happens, but the result is that your body will naturally wake up increasingly earlier, decreasing the amount of sleep you’re getting, explains Hans Van Dongen, Ph.D., director of the Sleep and Performance Research Center at Washington State University. By the time you hit your 60s, you could be waking up two hours earlier than you did in your 30s.