The U.S. Centers for Disease Control and Prevention (CDC) describes sleep deprivation as a "public health epidemic " linked to a wide range of medical issues, including hypertension, diabetes, depression, obesity and cancer. Yet, the demands of modern society increasingly can shorten the time for rest, speakers said 11 March at AAAS.
Adults need seven to nine hours of sleep per night, according to the National Sleep Foundation, but a CDC survey  found that some 50 to 70 million U.S. adults suffer chronic sleep and wakefulness disorders. More than 35 percent of nearly 75,000 survey respondents reported getting less than seven hours of sleep, on average, each night. The National Department of Transportation estimates  that drowsy driving causes 1,550 fatalities and 40,00 nonfatal injuries every year in the United States.
"It's a big problem," said Michael J. Twery, director of the National Center on Sleep Disorders Research at the National Heart, Lung, and Blood Institute. Most recently, he noted, researchers reported in Science  that sleep functions as a kind of "sewer system" for the brain, at least in mice, by flushing beta-amyloid, which is known to accumulate in the brains of patients with Alzheimer's disease.
Twery was one of three speakers who took part in a public program at AAAS on what neuroscience tells us about sleep, sleep disorders and dreams. The event  was the first of the 2014 series on Neuroscience and Society, organized by AAAS and the Dana Foundation.
Clifford B. Saper, professor of neurology and neuroscience at the Harvard Medical School and chair of the Department of Neurology at the Beth Israel Deaconess Medical Center said that "99 percent of scientists agree — a loss of sleep is deleterious." Saper and his colleagues have been studying the brain's suprachiasmatic nucleus, or SCN, which resets our daily circadian clock, and the genes that control wakefulness. The work is shedding light on why many older people may have more trouble falling and staying asleep.
Why do we dream? Sigmund Freud thought that dreams were a form of wish fulfillment. But according to Deirdre Leigh Barrett, assistant clinical professor of psychology in the psychiatry department at the Harvard Medical School, "Research is converging on the idea that dreams are simply thinking in another biochemical state." Dreams often seem to be a way of working through emotional and personal issues, she added, although they may sometimes offer creative inspiration to artists.
Sleep apnea and other medical disorders are often the cause of sleep deprivation, Twery noted. Yet, he added, too many of us are missing out on sleep by choice: "We choose to be awake," he said. "We choose to maximize our lives through wakefulness." Late-night eating should be avoided, Saper said. The National Sleep Foundation also suggests sticking to the same bedtime and wake-up routine every day, avoiding naps, and doing daily exercise, among other healthy sleep habits .