Sleeping With Lights On At Night Tied To Weight Gain In Women
A recent report published in Medical Journal Jama Internal Medicine on Monday revealed that keeping lights on while snoozing can become a cause of weight gain and obesity in women. The research was conducted on 43,722 women with an average age of around 55 in the United States.
The findings came from a cohort study named ‘Sister Study’. It enrolled women between 2003 and 2009 and included precise information on women’s sleeping habits like whether they sleep with lights or television on.
Further, self-reported sleeping habits of these women were categorized into four categories. The categories were: No light, small nightlight in the room, the light outside of the room, and light or television in the room. These habits were compared with the Body Mass Index of the women enrolled in the study.
Body Mass Index commonly referred to as BMI is a numeric value derived from a calculation involving body mass and height of the subject. It is a popular tool used to measure body fat and obesity.
According to the study, “Artificial light at night while sleeping was significantly associated with increased risk of weight gain and obesity, especially in women who had a light or a television on in the room while sleeping. Associations do not appear to be explained by sleep duration and quality or other factors influenced by poor sleep.”
Women who slept with more than one light on were categorized at the highest level of exposure. Women with no lights or a mask on while snoozing were classified as experiencing no artificial light exposure.
The researchers closely observed at each women’s sleeping habits and weight along with obesity risk if any.
The researchers found an increase of 10 % or more in BMI, along with a gain of at least five kilograms in the women sleeping with lights. Further, they are at a higher risk of being overweight, and a 33 % more risk of obesity as compared to women with no artificial lights.
The study found resemblance with another study published in 2016 in Journal of Endocrinology and Metabolism concluded: “Ambient light exposure, such as increased night time or evening light exposure and decreased morning light exposure, was independently associated with subsequent increases in obesity parameters.”
Limitations of this new study included no reporting of a change in the exposure of artificial lights at nights, information was self-provided and hence misses objectivity.
Another limitation with this research was that no information about the reason of keeping artificial lights at night was asked from the participants. Change in weight was also based on self-reported data, which is prone to misclassification, especially in higher BMI categories
