People who want to lose weight may want to consider sleeping longer at night, say U.S. researchers, who found that there is a link between sleep habits and weight.
According to the investigators, individuals who are 'short sleepers' (meaning they got less than six hours of sleep per night) are more likely to have on average a higher Body Mass Index (BMI) even if they are more physically compared to 'long sleepers' during the day. Their study appears to be the largest to show an association between irregular sleep and being overweight.
For the study purposes, the experts analyzed the sleep activity and energy expenditures of 14 nurses who had volunteered for a heart-health program at the Walter Reed Army Medical Center in Washington DC, where they were employed. The program included counseling on nutrition, exercise training, stress management and sleep improvement. Each participant was asked to wear an actigraphy arm band that measured total activity, body temperature, body position and other indicators of activity and rest.
The results revealed that those nurses who were identified as "short sleepers" had an average body mass index of 28.3 kg/m2. This is to compare with an average BMI of 24.5 for "long sleepers". Short sleepers also had lower sleep efficiency, experienced as greater difficulty getting to sleep and staying asleep, said a lead author of the research Dr. Arn Eliasson, of the Integrative Cardiac Health Project at Walter Reed Army Medical Center.
Body Mass Index is a widely used measurement that calculates a person's weight and height and is an indicator of body fat. Individuals with a BMI of 30 and up are considered to be clinically obese. "Normal" is defined as 18.5 to 24.9, and "overweight" between 25 and 29.9.
The investigators also found that ladies with extra weight were likely to be more physically active, compared to their counterparts with normal weight, taking significantly more steps than normal weight women. The overweight participants took an average of nearly 14,000 steps on a daily basis, compared to 11,292 for the participants with normal weight. The overweight women also burned about 1,000 more calories per day, on average, than their peers with normal weight.
"We found so many interesting links in our research. It opens up a number of possibilities for future investigation. Primarily, we want to know what is driving the weight differences, and why sleep and weight appear to be connected," said Dr. Eliasson and also added that individuals who do not get enough sleep might develop disruption in natural hormonal balances and could, therefore be experiencing the need to eat more. The expert said that stress may also play a critical role in both reducing the length and quality of sleep and increasing eating and other behaviors that may result in weight gain.
