Early morning light is essential. It makes everyone feel alive enough to kick start a good day. However, in a recent study, it seems like children who are more exposed to light earlier in the day tend to weigh more than children who are receiving bigger dose of light in the afternoon.
Having around 42 million children all over the world, under the age of five being classified as obese or overweight, it is indeed a breakthrough that such research was able to link overweight with an external factor, such as light.
Ph.D. student Cassandra Pattinson and her team studied 48 children aged three to five over the course of two weeks. The team measured each preschooler's sleep, activity, height, weight, and dose of light received each day.
"We found moderate intensity light exposure earlier in the day was associated with increased body mass index (BMI) while children who received their biggest dose of light - outdoors and indoors - in the afternoon were slimmer," says Ms. Pattinson, as quoted in the press release.
The team noted that unexpectedly, physical activity was not associated with the children's body mass index, as opposed to time of sleep and light exposure. Researchers did not limit light exposure to just the natural light coming from the sun, but also extended it to artificial light, including those given off by tablets, mobile phones, night lights and television.
Pattinson said it is known that the timing, intensity and duration of exposure to both artificial and natural light have acute biological effects on mammals, University Herald writes. The body clock is largely driven by dose of light and time of exposure. Such affects sleep patterns, body weight, hormonal changes, and mood.
While the previous research in adults links afternoon light exposure to increased body mass, it turns out that the present study found the opposite in children. Other known factors that affect obesity include calorie intake, decreased physical activity, short sleep duration, and inconsistent timing of sleep.
The research team also plans to conduct further studies on infants and figure out how the recent finding can be used to help children get rid of obesity.
Pattinson presented her findings at the ASA Sleep Downunder Conference in Melbourne.