If you're trying to lose weight and you want to make the most of every opportunity to lose those unsightly flabs, you might as well include reducing the amount of light in your bedroom at night on your to-do list.
Findings of a new study suggest that having too much light in your room during bedtime may compromise your efforts to lose fat.
In a new study published in the American Journal of Epidemiology on May 29, researchers involved over 113,000 women who were part of the Breakthrough Generations Study to find a link between obesity and light exposure at night. The Breakthrough Generations Study attempts to determine the root causes of breast cancer, a disease that caused over 500,000 deaths worldwide in 2011. Obesity is known to increases risks for breast cancer.
The researchers asked the participants to rate the amount of light they have in their bedroom at night and compared the answers with several measures of obesity. They found that even when the participants' physical activity, sleep duration, alcohol intake and smoking habits are taken into consideration, exposure to too much light at night is associated with increased risks for obesity.
"The odds of obesity, measured using body mass index, waist:hip ratio, waist:height ratio, and waist circumference, increased with increasing levels of LAN exposure, even after adjustment for potential confounders such as sleep duration, alcohol intake, physical activity, and current smoking," the researchers wrote.
The obesity-causing effects of light at night appear to have something to do with the body's natural clock. The artificial light can delay the production of the sleep hormone melatonin and mess up the body's circadian rhythm, which can affect mood and the way a person processes food. A study published in the journal Obesity early this year found an association between fewer hours of sleep and the tendency to eat more calorie-packed foods.
"Metabolism is affected by cyclical rhythms within the body that relate to sleeping, waking and light exposure," said study researcher Anthony Swerdlow, from the Institute of Cancer Research in London. Swerdlow, however, said that the particular reason for the association between obesity and light exposure at night still needs to be determined.
Still, health experts consider the findings of the study as crucial. "These findings add weight to previous results from animal studies that looked into how light exposure, circadian rhythms and metabolism could all be connected in some way," said Matthew Lam from Breakthrough Breast Cancer, the charity that funded the research.
