In a first-of-its-kind study, French researchers found that artificial blue light can synchronize the body clock under conditions in which natural light is scarce or unavailable.
They performed their experiment under real conditions involving crew members of the Franco-Italian polar research station Concordia, located in Antarctica.
Because the sun disappears there from May until late August, the 13 Concordia crew members who endure four months of complete darkness made excellent test subjects.
"Although the benefits of blue light for the biological clock have already been demonstrated in the past, all the studies were conducted under conditions that are difficult to reproduce under real conditions," says lead study author Claude Gronfier.
The internal body clock regulates sleep cycles based on the availability of natural light and the transition to darkness, known as circadian rhythms.
It is located in the brain and consists of over 20,000 neurons that control the release of hormones to regulate sleep and wake cycles.
Regular meals, exercise and body temperature all contribute to the upkeep of the body clock, although light is the most important.
In the study, researchers exposed crew members to a white light and a blue light (which actually appears white to the human eye), alternating on a weekly basis for a period of nine weeks.
Nothing changed other than the light: crew members were asked to maintain their daily routines for the sake of results.
The results not only showed increased sleep and increased motivation in the daytime during the weeks of blue light, but they also showed no disturbance in circadian rhythm.
On the flipside, circadian rhythms were disturbed during weeks of plain white light.
Results have encouraged researchers, who envision better lighting strategies for homes and workplaces in areas with limited light.
The study was published in PLOS ONE.
