Electric Lights Alter Daily Rhythms

Humans’ circadian clocks become skewed when they are exposed to electric lights but revert to a schedule more in tune with the sun when they go camping.

By | August 6, 2013

FLICKR, ANJANETTEWLong-term exposure to electric lighting has fundamentally altered humans’ circadian rhythms, according to a study published in Current Biology last week (August 1). But a week camping away from electric lights swiftly reset eight study participants’ circadian clocks.

“What’s remarkable is how, when we’re exposed to natural sunlight, our clocks perfectly become in synch in less than a week to the solar day,” coauthor Kenneth Wright, a University of Colorado Boulder integrative physiologist, said in a press release.

For the first week of the study, participants went about their ordinary routines at home. Next, they all went camping in the Rocky Mountains for a week without flashlights or electronics.

Throughout the study, the participants wore wrist monitors that logged light intensity, time of day, and activity. At the end of each week, the researchers measured the participants’ melatonin levels, which indicate circadian cycle status.

While going about their ordinary routine, the participants went to sleep at 12:30 a.m. on average, experiencing on onset of melatonin about 2 hours prior. In the wilderness, the participants’ circadian clocks were advanced by 2 hours; they experienced an earlier onset of melatonin, coinciding with sunset, and went to sleep sooner.

The experiment also showed that a week in the wilderness reduced the differences among the participants’ daily rhythms, with the schedules of early birds and night owls converging.


Add a Comment

Avatar of: You



Sign In with your LabX Media Group Passport to leave a comment

Not a member? Register Now!

LabX Media Group Passport Logo


Avatar of: GregNash


Posts: 1

August 8, 2013

How long did it take them to return to their TV-enduced circadian cycles?


Popular Now

  1. Birth of the Skin Microbiome
    Daily News Birth of the Skin Microbiome

    The immune system tolerates the colonization of commensal bacteria on the skin with the aid of regulatory T cells during the first few weeks of life, a mouse study shows.

  2. Inside a Lab Mouse’s High-Fat Diet
  3. Battling the Bulge
    Bio Business Battling the Bulge

    Weight-loss drugs that target newly characterized obesity-related receptors and pathways could finally offer truly effective fat control.

  4. How Gastric Bypass Can Kill Sugar Cravings
Life Technologies