Last year, a US study found that a one-hour increase in the average weekly sleep increased wages by 1.5% in the short run and by 4.9% in the long run. A new study found more sleep not only makes employees richer, it also helps them stay in shape.
Researchers from King’s College London, suspect that getting too little sleep affects the body’s hormones, triggering the body to want to eat more.
The findings published in the European Journal of Clinical Nutrition, found that sleep-deprived people – those who get less than five and a half hours a night – consumed an average of 385 calories per day more than those who had more than seven hours. That is equivalent to eating an extra four and a half slices of bread.
The study pointed out that an increased calorie intake of this magnitude can contribute to weight gain, since the main cause of obesity is an imbalance between calorie intake and expenditure.
The researchers explained that sleep was tied to calorie intake by the body’s clock, which synchronises bodily functions to the 24-hour pattern of the Earth’s rotation and the way the eye perceives light and dark.
Not having enough sleep disrupts the body clock and affects the regulation of key hormones such as leptin, which tells us when we are full, and ghrelin, the “hunger” hormone. This affects our metabolism, including the way we feel hunger and when we feel full, resulting in more food intake.
“Our results highlight sleep as a potential third factor, in addition to diet and exercise, to target weight gain more effectively. We are currently conducting a trial in habitually short sleepers to explore the effects of sleep extension on weight gain,” Haya Al Khatib, who led the latest research, told the Daily Mail Online.