Lack of Sleep Takes Toll on Brain Power

Feb. 9, 2000 (Atlanta) -- A sleepy person's brain works harder -- and accomplishes less. A study using real-time, state-of-the-art imaging shows that sleep deprivation has dramatic effects on the brain and how well it performs.

Researchers expected to find only sluggish activity in the brains of healthy young people who took a simple word test after staying awake for 35 hours. They found instead that while parts of the sleep-deprived brains churned with activity during the test, another part of the brain -- the language center -- shut down.

"Sleep deprivation is bad for your brain when you are trying to do high-level [thinking] tasks," study co-author J. Christian Gillin, MD, tells WebMD. "It may have serious consequences both on performance and on the way your brain functions."

Gillin's team at the University of California, San Diego, and the San Diego VA Medical Center found that the brains of some sleep-deprived study participants tried to overcome the language-center shut-down by shifting activity to another part of the brain. These individuals performed better on the memory test than their sleep-deprived peers, but not as well as they did when rested.

"What this shows is that the brain is very flexible," Monte S. Buchsbaum, MD, professor of psychiatry at Mount Sinai School of Medicine, tells WebMD. "This shows that the brain can move a task from one area to the other when you are sleep deprived, or when you get old."

Jim Horne, PhD, director of the sleep research laboratory at Loughborough University in England, notes in a commentary accompanying the study that the part of the brain that overworks in the sleep-deprived people normally is one of the most active areas of the brain. It is involved in complex functions such as updating working memory, planning, attention, sense of time, dealing with novel situations, and verbal fluency. "Some years ago, we suspected that if sleep offers some sort of recovery process, then the parts of the cortex that work hardest during wakefulness may be those that suffer the deprivation initially," he tells WebMD. "But what seems to be happening is that the functional part of the brain appears to be working even harder during compensation -- to no avail, because performance shows deterioration."

However, Horne says that this part of the brain gets its rest during the earliest stages of sleep. "Not all of sleep is for recovery. A particular part of sleep occurring in the early part of sleep is most important for [brain] recovery, and the latter part is not so important in that regard," he says. "As we can eat more food than we require and drink more fluids than we require, we may sleep more than we require. Rather than trying to extend one's sleep ? perhaps we should take short naps instead."

So how much sleep does one need, and how should one get it? Horne has an easy answer. "The amount of sleep we require is what we need not to be sleepy in the daytime," he says.

Gillin and colleague Gregory G. Brown, MD, are planning to use the new imaging techniques to find out exactly how one might get the right amount of sleep. "The current study is the beginning -- the opening wedge," he says. "A lot of work remains in determining whether short-term sleep deprivation is different than chronic deprivation, whether women respond differently than men, whether stimulating drugs have any effect, whether short naps provide respite, and, if so, how long a nap [is needed]."

Vital Information:

  • In a person who is sleep-deprived, one part of the brain shuts down while other parts will kick in to help compensate.
  • Regardless of the brain's attempt to overcome sleep deprivation, a sleep-deprived person cannot perform mental tasks as well as someone who is well-rested.
  • For brain recovery, the early part of sleep each night is the most important.