Sleep Loss and Daytime Performance

Sleep Loss and Daytime Performance

By Gregg D. Jacobs, Ph.D.

It has been widely reported by the media that sleep deprivation can have serious effects on our daytime functioning. Exactly what are the effects of sleep deprivation?

Sleep deprivation can have significant effects on performance if sleep loss is significant and occurs for several days without recovery sleep. For example, many studies show that if eight-hour sleepers are restricted to four hours of sleep for as little as a few days, their performance deteriorates on tasks like problem solving, reaction time and memory. However, the magnitude of these effects depends upon the person, how much sleep is lost, motivation and the circumstances under which sleep loss takes place.

Some individuals show a remarkable tolerance for sleep loss, particularly if the person is motivated to cope with sleep loss (examples would be dealing with a crisis, caring for a newborn, etc.) or if the sleep loss occurs under positive circumstances (excitement, a vacation, a social event, etc.). Also, the effects of sleep loss are more pronounced when people lose half of their normal sleep but less pronounced when they only lose one or two hours. Therefore, an eight-hour sleeper will show little or only moderate impairment in daytime functioning if restricted to six hours of sleep but will show more significant impairment when only allowed to sleep only four hours. And for every study that reveals impaired performance after sleep loss, other studies find minimal or no effects. These findings suggest that the effects of sleep loss are not consistent or robust.

Researchers are beginning to realize that the results of sleep deprivation studies are also confounded by the effects of stress. Many such studies involve highly stressful conditions that are far from routine, therefore it may the stress or the experiment that produces impairment after sleep loss. Similarly, real-life sleep loss typically occurs as a result of stress so we don't know if the performance decrements after sleep loss are due to sleep loss itself or the stress that causes the sleep loss.

And then there are the positive effects of sleep deprivation that are not reported or acknowledged by the sleep specialists who warn us of the dangers of sleep deprivation. For example, sleep deprivation is therapeutic for depression. In fact, sleep deprivation produces a faster improvement in depression than antidepressant medication and is considered by some researchers to be the most potent treatment for depression.

There is also research to suggest that individuals who need to maintain performance under challenging circumstances, such as rescue workers, armed services personnel, physicians and solo yacht racers, can actually maintain or improve their performance if they sleep in multiple short bouts throughout the day that total less than six hours. For example, solo yacht racers who adopt this schedule and reduce sleep needs to about five to six hours per day actually perform the best and win races. Many studies have shown that maintaining a small sleep debt actually helps us to sleep efficiently each night; when individuals are allowed to "sleep out", they eliminate all of their sleep debt and have a harder time falling and staying asleep. By depriving ourselves of a little bit of sleep each night, we sleep better due to a stronger sleep drive.