Medicine

Sleeping With a Light on Can Make You Gain Weight

Sleeping With a Light on Can Make You Gain Weight

Using this information, the scientists were able to study obesity and weight gain in women exposed to artificial light at night with women who reported sleeping in dark rooms.

Published Monday in JAMA Internal Medicine, the research by a team at the National Institutes of Health is the first to find an association between artificial light exposure and weight gain in women.

This observational study included almost 44,000 women in its analysis. Participants' weight was recorded at the start of the study, and they were followed for an average of 5.7 years.

"These results suggest that exposure to [artificial light at night] while sleeping may be a risk factor for weight gain and development of overweight or obesity", the researchers conclude.

Respondents reported exposure to artificial light at night (ALAN) from televisions, smart phones, computers, e-readers and tablets, which emit a short wavelength-enriched light or "blue light" that previous research has linked to melatonin suppression and circadian disruption. According to a new study, this could be the reason why you're gaining weight.

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"It's really important that you have that daytime-nighttime cycle, so that you appropriately regulate hormones, hormones that regulate your sleep, hormones that regulate your hunger, said lead author Dale Sandler, a scientist with the National Institute of Environmental Health Sciences, a division of NIH".

The study questionnaire asked whether the women slept with no light, a small nightlight, light outside of the room, or a light or television on in the room.

Daily exposure to light and darkness helps maintain our 24-hour body clock, which regulates metabolism, sleep-promoting hormones, blood pressure, and other bodily functions. Sleeping with a light on outside the room was associated with only slight increases in weight. However, their findings did not change when analyses controlled for characteristics that may be associated with exposure to light at night.

"Unhealthy high-calorie diet and sedentary behaviors have been the most commonly cited factors to explain the continuing rise in obesity", Dr. Park said.

Factors were taken into account, such as the place of domicile of the person (rural or urban), their level of income and the initial weight, in order to compare them to women in situations as similar as possible. "If these study findings are true and if they can be replicated then it's a very easy public health message to turn off the lights when you're sleeping". We know from experimental studies in people that light at night affects our metabolism in ways that are consistent with increased risk of metabolic syndrome.