Daijiworld Media Network - New Delhi

New Delhi, Nov 5: Going to bed earlier may do more than help people feel refreshed the next morning. A new study has found that earlier sleep timing could also contribute to greater weight loss among people with prediabetes, highlighting the importance of bedtime habits in managing body weight and improving metabolic health.

The study, published in the journal Nursing Research, examined nearly 200 adults with prediabetes who regularly slept for less than 6.5 hours a night. Researchers found that participants who went to sleep earlier experienced greater weight loss over an eight-week period.

Although the intervention did not produce significant improvements in blood sugar levels, the findings suggest that sleep timing, alongside sleep duration and quality, could be an important factor in weight management and diabetes prevention.

The researchers randomly divided the participants into two groups. Both groups underwent an eight-week lifestyle programme focusing on healthy eating, physical activity and stress management through weekly video sessions. However, one group received additional sleep coaching.

The coaching programme included guidance on sleep hygiene, maintaining consistent sleep schedules, gradually moving bedtime earlier and increasing total sleep duration. Participants were also taught to strengthen the association between their beds and sleep rather than using them for other activities.

All participants maintained daily sleep diaries. Researchers also used continuous glucose monitors to measure blood sugar levels and specialised wrist-worn actigraphs to track sleep patterns before and after the programme.

Both groups recorded improvements in sleep and weight loss. However, participants who received additional sleep coaching experienced greater improvements in sleep quality, reduced daytime sleepiness and a significant shift towards earlier bedtimes.

Susan Kohl Malone, assistant professor at New York University's College of Nursing and lead author of the study, said that when people fall asleep, and not merely how long they sleep, appears to be an important but often overlooked factor in weight management and metabolic health.

Interestingly, researchers found that earlier sleep onset was associated with greater weight loss irrespective of the group to which participants belonged. Changes in sleep duration alone did not show the same association.

The study indicated that every hour earlier participants fell asleep was associated with approximately 1.3 pounds (0.73 kg) of additional weight loss over the eight-week period.

Researchers identified several possible explanations for the association. Going to bed earlier may reduce opportunities for late-night snacking and unnecessary calorie consumption. People who remain awake late are more likely to eat outside their regular meal schedules, potentially increasing their overall calorie intake.

Sleep timing may also influence the body's metabolic processes. Insulin sensitivity and glucose tolerance generally decline at night, meaning that consuming food late in the evening could interfere with the body's natural metabolic rhythm. Earlier sleep may help reduce late-night eating and align food consumption with the body's optimal metabolic window.

Another possible factor is exposure to artificial light. Staying awake late often involves prolonged exposure to television screens, mobile phones and other electronic devices, which can disrupt the body's natural sleep-wake cycle.

Irregular sleep patterns and inadequate rest may also affect hormones regulating hunger and appetite. Increased activity of ghrelin, commonly known as the hunger hormone, can stimulate appetite and encourage greater food consumption.

Poor sleep has also been associated with elevated stress hormones such as cortisol, which may contribute to insulin resistance and changes in appetite, making weight management more difficult.

The researchers said the findings highlight sleep timing as a potentially useful component of weight-management strategies, particularly among people with prediabetes.

However, they cautioned that the eight-week intervention did not produce significant improvements in blood glucose levels. Going to bed earlier should therefore not be considered a treatment for prediabetes or a substitute for medical care, healthy eating and regular physical activity.

Maintaining a consistent sleep schedule, avoiding late-night meals and ensuring adequate sleep could instead complement established lifestyle measures aimed at preventing the progression of prediabetes to Type 2 diabetes.