By Jasminee Sahoye
With the switch to daylight saving time, the annual ritual of setting the clocks forward one hour in the run-up to Spring, a recent study found that losing as little as 30 minutes of sleep per day on weekdays can have long-term consequences on your body weight and metabolism.
“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 Prof. Shahrad Taheri, MBBS, PhD, professor of medicine at Weill Cornell Medical College in Qatar, Doha.
He added that this reinforces earlier observations that sleep loss is additive and can have metabolic consequences.
People often accumulate sleep debt during weekdays due to social and work commitments and try to make up for lost sleep over the weekend. But, according to researchers, 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.
“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,” Taheri said.
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 seven-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 six-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.
Another sleep related study found that restricting calories may improve obstructive sleep apnea and reduce high blood pressure in obese adults.
People with sleep apnea may experience pauses in breathing five to 30 times per hour or more while sleeping. It prevents restful sleep and is associated with high blood pressure, arrhythmia (abnormal heart rhythm), stroke and heart failure.
In a 16-week randomized clinical trial, researchers analyzed 21 obese people 20-55 years old with a history of sleep apnea. Researchers instructed one group to reduce their calorie intake by 800 calories per day, while another group continued their current diet.
Researchers found those in the calorie-restricted group had fewer pauses in breathing during sleep, lower blood pressure, higher levels of oxygen in their blood and a greater reduction in body weight.
“This study suggests that in obese patients with obstructive sleep apnea, moderate energy restriction can reduce not only body fat but also the severity of obstructive sleep apnea,” said Marcia R. Klein, M.D., Ph.D., co-author of the study and adjunct professor in the Department of Applied Nutrition at Rio de Janero State University in Brazil.
“So moderate energy restriction in these patients has the potential to reduce cardiovascular risk.”