Does the old adage, “the early bird gets the worm” still hold true? Not sure about the worm, but the latest research shows you might be a skinnier bird.
Recent research shows that exposure to morning light seems to be associated with learner body weight. No kidding! We’ve known for quite some time that chronic sleep deprivation leads to weight gain and obesity. However, several studies now indicate that morning light exposure influences body fat, metabolic function, and level of appetite regulating hormones. In women who are already exercising, research shows that there is a significant difference in BMI for those exposed to morning light versus those who are not and are of similar exercise patterns and caloric intake. Fascinating.
How can this be? It seems as though these findings fit into a growing body of evidence that suggest the complex relationship between our internal body clocks and the natural light-dark cycle are actually quite synchronized. This field of science and research is known as chronobiology and is gaining notoriety. Chronobiology is essentially what our ancestors have known for centuries, and is proving that we are still hard-wired cave people. Perhaps obvious, but now we have the data to prove that light is an important cue to synchronizing our internal clocks and helping our bodies perform optimally.
To better understand this relationship, researchers at Northwestern University recruited 54 adults from the Chicago area and had them wear wrist monitors for a week. The monitors tracked their exposure to light, as well as sleep duration and patterns for a week. The participants also kept daily logs of dietary intake, so the researchers could take into account caloric intake. This study published in April 2014, was the first of its kind to investigate the influence of both light levels and sleep on body weight in humans. The results were clear: the earlier the light exposure occurred during the day, the lower the BMI. This was true even after the researchers accounted for the variables of caloric intake, activity level, sleep timing, age or season. The optimal light level found to correlate with lower BMI was 500 lux of light, which is roughly equivalent to bright indoor lighting.
Get up early, lose weight. Can it really be this simple? Probably not, but perhaps another reason to get up and at ’em early making your exercise the day’s priority. Surrender to your primal instincts: sleep when its dark, rise with the sun. Just remember the sunscreen.