At Every Age, Feeling the Effects of Too Little Sleep

By JANE E. BRODY
Published: October 23, 2007

Surveys have shown that few of us past infancy and toddlerhood are receiving the amount of sleep our bodies and brains need to restore them to full function for the day ahead. And many of us — children, teenagers and adults of all ages — may pay a hefty price. More than intellectual prowess can suffer; though definitive data are still lacking, a chronic shortage of sleep has been linked to serious physical ills, including heart disease, diabetes and obesity.

Sleep deprivation seems to start early. A 2004 survey by the National Sleep Foundation found that on average, children in every age group from infancy through fifth grade failed to get even the low end of the recommended range of sleep.
The real agony emerges in adolescence. As children go through puberty, two things happen to make getting enough sleep problematic: they need more sleep than prepubescent children, not less — 9 to 10 hours a night — and their body clocks shift to a later time to fall asleep and, consequently, a later awakening.

The average eighth grader sleeps less than eight hours, and more than a quarter of high school and college students are chronically sleep deprived, they reported.“15 million American children are affected by inadequate sleep.” Sleep deprivation has been linked to poorer grades, moodiness and depression. Insufficient sleep in the teenage years has been associated with increased risks of disciplinary problems, sleepiness in class and poor concentration, not to mention traffic accidents.
With televisions and computers in their rooms, many teenagers cannot resist the temptation to stay up late, especially because their bodies do not begin to produce the sleep hormone melatonin until 1 a.m., as opposed to 10 p.m. in most adults.

Harmful effects on adult health have been associated with sleeping too little and with sleeping too much. Studies suggest that adults who sleep seven to eight hours a night are the healthiest. About a third fall into that range. More than a third sleep less than seven hours, and nearly a third sleep more than eight hours.
A six-year study of more than one million adults found the highest mortality rate among those who slept less than four hours or more than eight hours a night. The lowest death rates were found among those who averaged six to seven hours of sleep. People who sleep less tend to weigh more.