Ever feel like you don’t get enough sleep? You’re not alone. The National Institutes of Health recommends dedicating 7–8 of the 24 hours we are given in a day to sleep. Yet, in a 2013 survey, the National Sleep Foundation found that Americans are getting an average of six hours and 31 minutes of sleep on work nights. According to a Gallup poll from the same year, 40% of us get less than the recommended amount, down more than an hour from 1942. A lot has changed since the 1940s, but our need for sleep has not.