Study: How Weight Affects Sleep Quality

A new study from the Perelman School of Medicine at the University of Pennsylvania has revealed that time spent on certain sleep stages were affected by the person's individual body composition and caloric intake.

"In a culture of increasing pressure to sacrifice sleep to maintain productivity, this research adds to the body of knowledge on how lifestyle behaviors may influence the quality of our sleep," said Andrea M. Spaeth, PhD, postdoctoral fellow and lead author on the study, in a statement.

The study was funded by National Institutes of Health and the U.S. Department of the Navy, Office of Naval Research and will be presented at SLEEP 2016, the 30th annual meeting of the Associated Professional Sleep Societies LLC.

According to a press release from University of Pennsylvania, the researchers enrolled 36 healthy adults for the study. The participants spend two consecutive nights of 10 hours in bed per night at the Hospital of the University of Pennsylvania.

The food and drink intake of each participant were measured every day. On the morning after the first night, researchers assessed the body composition and resting energy expenditure of the participants. The researchers also used polysomnography to record the physiological changes occurring in sleep on the second night.

The researchers then discovered that body mass index (BMI), body fat percentage and resting energy expenditure were not significant predictors of sleep stage duration. However, overweight adults tend to spend higher percentage of their sleep in the rapid-eye movement (REM) stage. Increase protein intake may also likely to lead into more REM sleep and lesser stage 2 sleep.

During the REM sleep, the heart beat and breathing may become faster, resulting to less restorative sleep. This is the stage when dreams typically occur.

On the other hand, stage 2 sleep occurs when a person's heart rate and breathing are relatively normal and his/her body temperature lowers slightly.

Researchers are recommending further studies to understand the biological mechanism behind the relationship of protein intake and REM sleep.