

Ambient light influences brain functions and other aspects of human physiology, such as circadian rhythm, heart rate and hormone release.

While these functions have long been recognized and studies have looked at the part of the brain that induces these responses at nighttime, little has been known about daytime responses to light.

But Gilles Vandewalle of the University of Liege, Belgium, and colleagues wanted to see if light exposure has similar effects on brain function during the day, when we are naturally exposed to light.



This boost was correlated with regions of the brain that are involved in alertness and some cognitive processes and can briefly prevent the sleepiness developed in continuous darkness, the researchers report in the Aug. 22 issue of the journal Current Biology.


"So light affects these regulatory systems at the cerebral and behavioral level," he explained. "This could be relevant for demanding jobs for example, usually performed by tired people."

Tired people can be found in offices everywhere, from the equator, where the sun shines down directly, to the Arctic Circle, where for half the year folks get much less direct sunlight.

