WEDNESDAY, June 30 (HealthDay News) -- Brain energy may
replenish itself during sleep, a new study suggests.
Experiments with rats revealed that during the initial stages of
sleep there is a dramatic increase in cellular energy levels in
brain regions that are active during waking hours. The findings
suggest that this energy boost reinvigorates brain processes that
are required for normal functioning while awake.
The study appears in the June 30 issue of the journal
Neuroscience.
While it's known that a good night's sleep helps restore body
and mind, it's been difficult to pinpoint the actual biological
processes that occur during sleep, researchers at the Boston VA
Healthcare System and Harvard Medical School said in a news release
from the journal.
For this study, researchers measured levels of adenosine
triphosphate (ATP) -- the energy currency of cells -- in rats.
During non-REM sleep, there was an overall decrease in brain
activity but an increase in ATP levels in four key brain regions
normally active during wakefulness.
When the rats were awake, ATP levels were steady. When the rats
were made to stay awake three to six hours past their normal sleep
times, ATP didn't increase.
The findings suggest that a certain amount of sleep is necessary
for an ATP surge, which may power restorative processes in the
brain, the researchers said.
The research was supported in part by the Department of Veterans
Affairs and the National Institute of Mental Health.
More information
The U.S. National Institute of Neurological Disorders and Stroke
has more about
sleep.