Researchers from the University of Pennsylvania analysed sleep patterns among 36 healthy adults who experienced two consecutive nights of 10 hours in bed per night at the university hospital.
Using polysomnography, the researchers recorded physiological changes that occur during sleep on the second night. Body composition and resting energy expenditure were assessed on the morning following the first night of sleep, while food and drink intake was measured each day.
The researchers found that body mass index (BMI), body fat percentage and resting energy expenditure were not significant predictors of sleep stage duration, but that overweight adults exhibited a higher percentage of time spent in the rapid-eye movement (REM) stage of sleep than normal-weight adults.
REM is a sleep stage when dreams typically occur characterised by faster heart rate and breathing. The researchers also found that increased protein intake predicted less Stage 2 sleep and the period when a person’s heart rate and breathing are relatively normal and his/her body temperature lowers slightly, it predicted more REM sleep.