Health & Medicine

Night Shifts Disrupt Circadian Rhythm; Increases The Risk Of Weight Gain

Kathleen Lees
First Posted: Nov 17, 2014 11:02 PM EST

Recent findings published in the Proceedings of the National Academy of Sciences (PNAS) show that night shifts could be dangerous when it comes to weight gain.

Researchers at the University of Colorado Boulder recruited 14 healthy adults for a six-day experiment that took place at the University of Colorado Hospital's Clinical and Translational Research Center. For the first two days of the study, the participants slept normally. Their sleeping schedule was then changed to a three-day shift schedule, forcing participants to work at night and sleep during the day. Yet they still had the opportunity to sleep for eight hours.

Throughout the experiment, the researchers controlled meals so that the participants ate the same amount of food that they would normally consume in order to maintain weight, with stable calorie consumption throughout.

Findings revealed that shift work typically caused an issue in circadian rhythm, which is often times linked to weight gain and other health issues.

"When people are on a shift work-type schedule, their daily energy expenditure is reduced and unless they were to reduce their food intake, this by itself could lead to weight gain," said Wright, director of CU-Boulder's Sleep and Chronobiology Laboratory. "Shift work goes against our fundamental biology. Shift work requires our biological day to occur at night and our biological night to occur during the day and that's very difficult to achieve because the sun is such a powerful cue. We can have some change in our clock--a couple of hours--but then on days off, it goes right back. Shift workers never adapt."

Those who slept during the day were able to burn more fat and stay in shape more, which can be crucial to overall health and well-being.

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