Cutting Belly fat Improves Sleep Quality

Good sleep means good physical and mental health. Chronic sleep disruption leads to cardiovascular problems, high blood pressure and is a sign of obesity.

A new study undertaken by researchers at John Hopkins reveals that people who are overweight or obese can improve their quality of sleep by cutting down their weight either through dietary changes alone or from diet combined with exercise.

"We found that improvement in sleep quality was significantly associated with overall weight loss, especially belly fat," says Kerry Stewart, Ed.D., professor of medicine at the Johns Hopkins University School of Medicine and director of clinical and research exercise physiology.

Nearly 77 people were registered for the six month study. All 77 were suffering from either type 2 diabetes or were pre-diabetic. The participants, all of whom were also overweight or obese, were randomly assigned to one of two groups.

The researchers made one group undergo a weight loss diet and supervised exercise training, while the other group only had diet intervention. A total of 55 participants completed all phases of the study.

The participants were also made to fill in the Hopkins Sleep Survey, at the beginning and end of the study to identify sleep problems including sleep apnea, daytime fatigue, insomnia, restless sleep, excessive sleep or sleepiness and use of sedatives to aid sleep.  In addition,their body mass index and amount of abdominal fat were also measured at the start and end of the study.

On conducting this experiment, the researchers noticed that both the groups, those assigned to a weight loss diet plus supervised exercise and those who only went on a diet, lost around 15 pounds on an average. With the help of magnetic resonance imaging (MRI) they assessed the amount of belly fat lost, and it was about 15 percent.

There were numerous sleep problems that were registered by the participants, but no common problems were seen. Hence, the researchers analyzed a composite score, which reflects overall sleep health. They found that both groups improved their overall sleep score by about 20 percent with no differences between the groups.

"The key ingredient for improved sleep quality from our study was a reduction in overall body fat, and, in particular belly fat, which was true no matter the age or gender of the participants or whether the weight loss came from diet alone or diet plus exercise," says Stewart.

Stewart is the senior author of the study, which was presented at the American Heart Association Scientific Sessions on November 6, 2012 by lead author Soohyun Nam, Ph.D., who is now at the Yale University School of Nursing. Her presentation was titled: "Predictors of Sleep Quality Improvement Among Overweight or Obese Individuals: A Randomized Controlled Trial."