Skimping on sleep leads to weight gain at the rate of one pound (a little under half a kilogramme) every six weeks, a small study suggests
Experts from Columbia University in the United States found that shortening the amount of sleep by 78 minutes per night (just under 1.5 hours) led to one pound on average weight gain and increased the likelihood of people being sedentary
Study leader Dr Marie-Pierre St-Onge, a professor of nutritional medicine in Columbia’s department of medicine and institute for human nutrition, said: “Our study shows that getting adequate sleep may help reduce the risk of weight gain and obesity-related conditions like heart disease and diabetes
“People tend to gain weight over the course of their adulthood, and obesity is a major risk factor for heart disease.”
Previous studies have shown that severe sleep deprivation in the short term leads to changes in appetite and overeating, which can contribute to weight gain
However, the researchers wanted to look at a more realistic scenario, where people lost more than an hour of sleep over a longer period of time
Prof St-Onge said: “These (previous) studies only show us what happens under the most extreme conditions and don’t tell us if mildly sleep-deprived people, like a lot of Americans who get five or six hours of sleep a night, will gain weight.”
To investigate the more realistic scenario, which the team think affects about a third of adults, some 95 adults who usually get seven or eight hours of sleep were recruited
All of them were told to delay their normal bedtime by 90 minutes for one six-week phase (although the end result was an average delay of 78 minutes) and to get the usual amount of sleep for the following six weeks
People wore a wrist monitor to track sleep, and changes in body weight, waist circumference, body composition and fasting levels of several hormones known to increase or suppress appetite were recorded
Study first author and Columbia assistant professor of nutritional medicine Dr Faris Zuraikat said: “While the one-pound weight gain observed with modest sleep curtailment is not overwhelming, it is important to remember this is occurring over just six weeks
“Our study was designed to mimic sleep patterns that most adults experience chronically
“When extrapolated to a full year, we would expect that losing less than an hour-and-a-half of sleep per night could result in clinically meaningful weight gain.”
Sedentary time also increased by an average of 17 minutes per day during the six-week period, and by nearly 30 minutes per day for men and postmenopausal women
“Even when we accounted for the fact that they were awake longer when sleep was shortened, participants spent more time being inactive than when they got adequate sleep,” Asst Prof Zuraikat said
“This is notable, as people who are more sedentary have elevated risk for chronic diseases.”
A previous study on the same participants found that women with increased cardiometabolic risk who shortened their sleep by around 80 minutes a night over six weeks had increased insulin resistance, a risk factor for type 2 diabetes
The effects were also more pronounced in postmenopausal women
In another study of the group, the researchers found that men and women with elevated heart risk had an influx of inflammatory cells in the heart after losing sleep
Prof St-Onge said: “Though more research is needed to further understand how sleep restriction leads to weight gain, all of our findings suggest that insufficient sleep increases the risk of obesity-related conditions like type 2 diabetes and heart disease
“Now we need to understand the health effects of improving sleep in those who fail to get adequate sleep on a regular basis.”
The study was published in the Annals Of Internal Medicine. – PA Media/dpa
