Research: Artificial Light at Night Linked to Obesity in Women

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Association of Exposure to Artificial Light at Night While Sleeping With Risk of Obesity in Women


I am sure you are inundated with news articles talking about the importance of good quality sleep to promote health. We know that the use of electronic devices with blue lights preceding bedtime can inhibit sleep. The lights energize the mind and increase cortisol levels and this limit sleep. There is no denying this link to poor sleep, weight gain, and poor health.

So what is artificial light? Artificial light is any light source that is not natural. In other words, it is not the sun and it is not the moon. Sources could include things like you cell phone, a charger plugged into the wall, a night light, a lamp on a bed side table, light from another room, or even a TV.

As a medical provider, I have long suspected that artificial light during sleep may hinder the quality of but the research to back up my concern is limited and quality is suspect. In fact, short sleep, poor sleep, and blue light prior to sleep have been associated with obesity, but to date the association between exposure to artificial light at night while sleeping and obesity is largely unknown. So, can artificial light at night while sleeping associated with weight gain and obesity?

This question was the subject of a study released in 2019​[1]​. The study looked at nearly 44K female patients and their exposure to artificial light at night while they sleep and the effect of this exposure on body fat and obesity. Researcher eliminated shift works because shift workers have a sleep schedule, quality, and duration issues that may affect the results of the data and cause a risk of obesity by itself.

The study revealed that compared with no artificial light, sleeping with a television or a light on in the room was associated with gaining 5 kg or more per patient. This was a significant increase in weight gain. These results suggest that exposure to artificial light while sleeping may be a risk factor for weight gain and obesity.

Although you may argue that this must be due to poor sleep and interruptions in the subjects sleep. The association of poor sleep to light exposure do not appear to be explained by sleep duration and quality. The finding appears to factors influenced by the light itself and not an effect of poor sleep itself.

The bottom line: Exposure to artificial light at night while sleeping is associated with increased weight and a clear risk for obesity. I would recommend that artificial light exposure be limited at night and just prior to going to sleep. More research is needed to confirm and quantify the risk.

  1. [1]
    Y.-M. M. Park, A. J. White, C. L. Jackson, C. R. Weinberg, and D. P. Sandler, “Association of Exposure to Artificial Light at Night While Sleeping With Risk of Obesity in Women,” JAMA Intern Med, Jun. 2019 [Online]. Available:
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About the Author

I am a family physician who has served in the US Army. In 2016, I found myself overweight, out of shape, and unhealthy, so I made a change to improve my health. This blog is the chronology of my path to better health and what I have learned along the way.

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