A good snooze is key when it comes to preventing colds. In one JAMA Internal Medicine study, researchers gave 153 healthy men and women nasal drops containing rhinovirus and tracked their sleep habits. They found that people who regularly got less than seven hours of sleep were three times more likely to come down with a cold than those who slept eight hours or more each night. The National Sleep Foundation recommends aiming for at least 7 to 9 hours per night. Can’t seem to doze off?