Some of us may get in the habit of watching TV in the bedroom and doze off to sleep. It could a favorite show, a movie or the news. Regrettably, recent research shows that watching TV and nodding off in bed may result in weight gain. While the research was based on women participants, the consequence also likely to apply to men.


The research, published in the June 2019 edition of Journal of the American Medical Association, Internal Medicine, involved 43,722 women from the United States and Puerto Rico. Also, these women ranged in age from 35 to 74 with an average age of 55. In addition, women had no history of cancer or cardiovascular diseases. Furthermore, the study excluded shift workers, day-time sleepers, and pregnant women.

The study reported that women, who slept with the TV or another light in the room on, were at an increased risk of weight gain or even become obese. Moreover, the study found these outcomes not only over the six-year study period (2003 to 2009) but also in the follow-up years ending in August 2015.

Meanwhile, the study also found as the association between the brightness of the light and weight gain. For example, a small nightlight has a negligible effect on weight gain. While light from outside the room resulted in a 3 percent chance of gaining 11 pounds. Finally, the most impact coming from a bright TV screen or standard lights left on in the room.



Most noteworthy, the study reported that women who slept watching TV or a light in the room had a 17 percent chance of gaining about 11 pounds and increasing BMI by 10 percent, over about five years as compared to women who slept in darkness. Also, they had a 22 percent chance of becoming overweight, meaning weighing too much or a BMI greater than 24.9. Finally, these women had a 33 percent chance of becoming obese, meaning having too much body fat or having a BMI exceeding 30. In fact, these women had a BMI ranging from 25 to 30. Incidentally, a normal or healthy BMI ranges from 18.5 to 24.9.

Furthermore, these women had inconsistent waking and bedtime hours as well as not getting enough sleep, taking a long time to fall asleep, wake up at night or take naps during the day.


Especially relevant, the study only found an association between sleep environment and weight, not a cause and effect.

The study also reported that artificial light during sleep likely disrupted circadian rhythms, melatonin signaling, and sleep. All these factors negatively impacted metabolism which, in turn, contributed to weight gain.

Most of all, daily exposure to light and darkness is important to maintain the 24-hour body clock. In fact, this body clock helps regulate metabolism, sleep-promoting hormones, blood pressure, and other body functions. Moreover, disrupting the body clock may cause poor health, increasing the risk of high blood pressure, diabetes, depression, and obesity.

Another Study

Meanwhile, another 2016 study, in the Journal of Clinical Endocrinology and Metabolism, reported increased light exposure during sleep of older adults resulted in a ten percent increase in BMI over a 10 period.


So, while a good diet and physical activity may help manage weight, it is also important to have good sleep habits. In fact, the takeaway from this study is that it is important to sleep in a room with no artificial light. That means, no TV, computer screens, cell phone screens, and no lights from other rooms. And, if you are exposed to light from the outdoor, through windows, close the curtains.