People who work during night face higher chance of becoming obese compared to those who work in day shifts, says a new study.
Fewer calories are burned while sleeping during day than at night, the research said. Thus, working night shifts can lead to greater risk of obesity. The new study has revealed that night shift patterns slow down metabolism of people, causing them to use less energy.
The study by the University of Colorado Boulder followed 14 healthy adults. For the first two days, a normal sleeping pattern was followed at night. And they stayed awake during the day. Later, a three-day shift was taken up where their routines were reversed.
"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 Kenneth Wright, director of CU-Boulder's Sleep and Chronobiology Laboratory and senior author of the paper.
When the participants took to the shift work schedule, the timing of their meals got altered but the total amount of calories remained the same. They were made to sleep for eight hours regardless of whether the timings were during day or night.
The researchers found that total daily energy spent decreased when they followed the shift work routine.
The body's primary circadian clock regulates sleep and eating and this is in the brain. But other body tissues such as liver, which regulates blood glucose levels, also follow circadian clocks. When circadian clocks are disrupted, those working in night shifts it may develop obesity. Wright said, "Shift work goes against our fundamental biology."
Shift work has been linked to a plethora of health problems, including an increased risk of diabetes, heart disease and stroke.