Sleep Timing Matters: New Study Links Earlier Bedtimes to Weight Loss

The time when a person goes to sleep and falls asleep may influence weight reduction more strongly than the number of hours slept. This is reported in a new study by researchers from the Rory Meyers College of Nursing at New York University.

The researchers concluded that bedtime may play a larger role than previously assumed. According to their data, the link did not depend on how many hours a person slept each night.

Study leader Susan Cole Malone, an associate professor at the Rory Meyers College of Nursing, said: "It appears that the timing of our sleep, and not only the number of hours we sleep, is an important factor that we should have taken into account when discussing weight reduction and metabolic health."

How the Study Was Conducted

The study involved 196 people aged 21 to 64 with prediabetes. This is the term for a condition in which blood glucose levels are above normal but do not reach the level of type 2 diabetes. People with prediabetes have a high risk of developing type 2 diabetes, particularly with excess weight or obesity, elevated blood pressure, or low physical activity.

Participants were randomly divided into two groups. The first took part in an eight-week programme to improve lifestyle and formed a control group. The second took part in the same programme but also received training and consultations on improving sleep habits. All participants usually went to bed before 6:30 a.m. at night.

What the Researchers Found

Sleep improvement classes did not noticeably change blood glucose indicators, although participants reported that they became less tired and more active during the day. When analysing the data, the researchers found a regular pattern among people who followed the sleep recommendations.

Those who started going to bed earlier showed notable changes in blood glucose levels, regardless of the number of hours they slept. According to Malone, earlier sleep may help reduce late-night snacking and bring mealtimes more in line with the period of greatest efficiency in metabolising nutrients.

The results were published in the journal Nursing Research. According to the researchers, for every hour that bedtime was later than usual, participants lost on average about 1.3 pounds (around 0.6 kilograms) over eight weeks. The link between sleep timing and weight loss was maintained regardless of the total number of hours slept.

Possible Explanations and Limitations

The scientists suggest several possible causes. Apart from a smaller number of late-night snacks, earlier sleep may reduce screen time and the effect of artificial light at night. It may also be linked to changes in the work of the sympathetic nervous system, which responds to stress. In addition, it may affect ghrelin, the so-called 'hunger hormone', which takes part in regulating appetite.

The authors emphasise that the study cannot be considered conclusive. The experiment was conducted only with people in the prediabetes risk group and lasted eight weeks. For this reason, the results are difficult to extend to everyone. In addition, the study does not show that earlier sleep was a direct cause of weight reduction.

Even so, according to the researchers, the work opens a new direction in the study of sleep and health. Besides the number of hours of sleep, it is important to examine the moment of sleep itself, its correspondence to the body's biological rhythms, and its effect on metabolism and weight control.

Source: skynewsarabia.com