Little known but widespread (an estimated 9 percent of women and 12 percent of men in the United States suffer from it), sleep apnea is a condition that causes breathing to stop five to 30 times per hour during the night. For some, it's caused by mixed signals from the brain to the breathing muscles, known as central sleep apnea. But in most cases, the cause is obstructive sleep apnea, which makes the throat muscles relax and close up. The patient often doesn't wake up but is robbed of deep sleep, leading to morning headaches and daytime sleepiness. The resulting lack of oxygen in the blood and stress on the heart can lead to high blood pressure, boosting stroke and heart attack risk.

Experts believe that the nation's soaring obesity rates mean that more people are suffering from sleep apnea. (An obese neck is more likely to collapse in on itself during slumber.) But the majority of sufferers don't know they have it. A sleep-lab analysis is often needed to verify the condition. Treatments include sleeping on your side, surgery to remove oversized tonsils, or a continuous positive airway pressure (CPAP) mask, which gently blows air into the throat, keeping airways open. But sleep specialists stress that staying at a reasonable weight and avoiding alcohol can easily prevent, and even reverse, sleep apnea.

For gentle, effective nighttime remedies read our related article on natural sleep aids.