Is Sleep the New Vital Sign?

Does it seem as though everybody is tired all the time? In a nation where people value long hours of hard work, guzzle more than 100 million cups of coffee a day, and watch television obsessively, sleep has suffered. Average nightly sleep duration has fallen from approximately 9 hours in 1910 to 7 hours in 2002. Many people often sleep no more than 5 to 6 hours a night, even though studies show that most people need between 7 and 8 hours. An estimated 20% of the population regularly experiences fits of irresistible daytime sleepiness.

Sleep deprivation is not always the result of lifestyle choices or nighttime work schedules (1 in 5 workers are employed in shift work). Sleep disorders can also be at fault. An estimated 10% to 15% of Americans have severe or chronic insomnia—difficulty initiating or maintaining sleep or waking too early—according to the National Institutes of Health. Sleep apnea also disrupts the sleep of an estimated 5% of Americans, leading to as many as hundreds of awakenings a night when the victims of this disorder struggle to breathe. Restless legs syndrome also causes frequent awakening among 5% to 10% of the U.S. population. People with this disorder awaken after moving their lower extremities to relieve constant, unpleasant sensations in the legs and feet.

Although sleep deprivation is common, over the course of weeks and months and years it has insidious effects on quality of life and on health. For example, too little sleep increases a person's chance of having an accident. Sleep-deprived people also often feel listless. Now, studies link sleep deprivation to obesity, type 2 diabetes, metabolic disorder, heart problems, psychiatric disorders, and dementia. “Sleep is a pillar of a healthy lifestyle. The magnitude of its effect on health is likely similar to the effects …