earlier bedtime and weight loss in prediabetes study, Digi Mart USA News (New York University, New York): New research from New York University’s Rory Meyers College of Nursing suggests that when people fall asleep may matter more for weight loss and metabolic health than how many hours they sleep. Lead author Susan Kohl Malone, an assistant professor at the college, said the timing of sleep appears to be an overlooked factor.
The trial involved 196 adults aged 21 to 64 who were at high risk of developing type 2 diabetes and consistently slept less than 6.5 hours a night. Participants were randomly assigned either to an eight-week lifestyle program, which served as the control, or to the same program with an added sleep-coaching component.
The sleep coaching did not change blood sugar readings, even though participants reported feeling more alert during the day. However, among those receiving sleep coaching, people who went to bed earlier showed a meaningful change in blood sugar levels, regardless of how many hours they slept.
Across both groups, falling asleep earlier was linked to more weight loss over the eight weeks, independent of total sleep time. On average, each hour earlier was associated with about 1.3 pounds (0.6 kg) lost.
The researchers suggested possible explanations, including less late-night eating, reduced screen time and artificial light exposure, and biological changes involving the sympathetic nervous system and the hormone ghrelin.
The researchers noted that the findings are not conclusive and have many limitations. Daytime sleepiness was self-reported, and glucose levels did not change across both cohorts.
Malone said the results raise the possibility that earlier sleep onset could be a promising target for improving metabolic health, though more research is needed. The study was published in the journal Nursing Research.
