The Effects of Lost Sleep
An NIH State-of-the-Science Conference focused on the public health issues of chronic insomnia - including the larger impact that is not often noticed. When children and the elderly (particularly nursing home residents) suffer from insomnia, parents and caregivers also suffer. Employers suffer when an insomniac's work performance is affected.
Most people need between seven and eight hours of sleep each night to feel refreshed and function optimally, says Hunt. "Obviously there's some variation, some people intrinsically need more sleep than others. A few people skip by successfully long-term getting less sleep - but that's a very small number."
If you're getting less sleep than your body needs, there can be serious consequences.
"There's recent evidence showing -- in men and women in several countries -- that chronic sleep deprivation increases risk of early death," Hunt tells WebMD. "Studies are showing that people who get less sleep are at greater risk for heart disease and heart attacks. And perhaps the hottest area of research has shown a link between chronic sleep deprivation and risk of overweight and obesity. These studies articulate the price society pays in not getting a good night's sleep."
The affect on our functional status was borne out in the 2005 Sleep in America survey. Over one-quarter of working adults - 28% -- said they had missed work, events and activities, or made errors at work because of sleep-related issues in the previous three months.
Laboratory studies have confirmed this impact on performance. In one small experiment, 16 young adults were allowed only five hours of sleep for seven nights. As the week wore on, the volunteers showed increasing difficulty performing tasks.
It's true, some people can get by just fine with less sleep. One study found that there are significant differences in impairment among sleep deprived volunteers - suggesting that vulnerability to sleep deficits varies greatly.
But for most people, getting less than six hours sleep translates into a bigger sleep debt than they may realize. Over a two-week period, missing out on the recommended eight hours of nightly sleep adds up to two full nights' sleep debt, one study found. If you're averaging only four hours a night, your brain reacts as though you haven't slept at all for three consecutive nights.
The most worrisome part: Many people are too tired to realize how sleep-deprived they are, experts say. But they have slower reaction time, weaker memory, and other thinking impairments.