Well-Planned Naps Boost Brainpower
Sleep, along with nutrition and exercise, shapes the backbone of overall health, yet 40 percent of Americans get an insufficient amount, according to a recent Gallup survey, and the potential health risks are considerable. “Sleep deprivation affects every organ system and disease state,” and is associated with higher rates of cardiovascular disease, diabetes, obesity, cancer and mortality, says Michael Breus, Ph.D., a clinical psychologist in Scottsdale, Arizona, and founder of TheSleepDoctor.com.
“It’s best to get seven to eight hours of sleep in one big block at nighttime,” counsels Breus. Yet the circadian rhythm dictates two peaks of sleepiness every 24 hours—one in the middle of the night and another 12 hours later, says Dr. Lawrence Epstein, director of the sleep medicine program at Boston’s Brigham and Women’s Hospital. Interacting with the circadian rhythm is the homeostatic rhythm, which causes greater sleepiness the longer we’re awake. Both circadian and homeostatic sleepiness elevate by mid-afternoon, resulting in the familiar 4 p.m. slump. Siesta cultures split sleep, notes Epstein, slightly reducing nighttime sleep, but devoting time midday to nap.