Losing 30 minutes of sleep per day may promote weight gain and adversely affect blood sugar control

"While previous studies have shown that short sleep duration is associated with obesity and diabetes, we found that as little as 30 minutes a day sleep debt can have significant effects on obesity and insulin resistance at follow up," said lead study author Professor Shahrad Taheri, MBBS, PhD, professor of medicine at Weill Cornell Medical College in Qatar, in Doha. "This reinforces earlier observations that sleep loss is additive and can have metabolic consequences."

Because of social and work commitments, people often accumulate sleep debt during weekdays and make up for lost sleep over the weekend. But weekday sleep debt may lead to long-term metabolic disruption, which may promote the onset of, or exacerbate the progression of, type 2 diabetes mellitus.

"Sleep loss is widespread in modern society, but only in the last decade have we realized its metabolic consequences," Taheri said. "Our findings suggest that avoiding sleep debt could have positive benefits for waistlines and metabolism and that incorporating sleep into lifestyle interventions for weight loss and diabetes might improve their success."

Professor Taheri and his colleagues recruited 522 patients with newly diagnosed type 2 diabetes mellitus in the Early Activity in Diabetes trial and randomized them into one of three groups: usual care, physical activity intervention, or diet and physical activity intervention.

Participants completed 7-day sleep diaries and calculated their weekday sleep debt. At baseline, the researchers recorded their height and weight to determine obesity status, measured their waist circumference for central adiposity, and analyzed their fasting blood samples for insulin sensitivity.

At baseline, compared with participants who had no weekday sleep debt, those who had weekday sleep debt were 72% more likely to be obese, and by the 6-month mark, weekday sleep debt was significantly associated with obesity and insulin resistance.

At 12 months, for every 30 minutes of weekday sleep debt at baseline, the risk of obesity and insulin resistance was significantly increased by 17% and 39%, respectively.

The authors advise that future interventions designed to slow progression or reverse metabolic disease should consider all factors -- including sleep -- that affect metabolic function. Looking toward future research, they recommend that consistent optimum sleep hygiene and education may be a key component of successful future trials in metabolic disease control.

Diabetes UK and UK National Institute of Health research funded this study.