In a randomized, placebo-controlled, two-by-two factorial study, Bogh and colleagues evaluated 195 adults with obesity (BMI, 32 to 43 kg/m²). During an 8-week, low-calorie diet period, the participants lost an average of 12% body weight. The participants were then randomly assigned to 1 year of weight loss maintenance with placebo; exercise (4 times per week) and placebo; Saxenda 3 mg (liraglutide, Novo Nordisk) daily; or exercise and liraglutide.
The researchers measured participants’ sleep duration and efficiency with accelerometers and the Pittsburgh Sleep Quality Index (PSQI) before the diet period, after the diet period (baseline) and after 26 and 52 weeks of maintenance. A global score of five or more on the PSQI was considered poor sleep and less than five was good sleep.
Overall, sleep quality, efficiency and duration increased for all participants after the diet period. However, participants who got less than 6 hours of sleep per night at baseline increased their BMI by an average of 1.3 kg/m² (P = .02) by week 52 compared with participants who slept 6 to 7 hours each night, according to Bogh and colleagues. Moreover, poor sleepers at baseline increased their BMI by 1.2 kg/m² (P = .01) compared with good sleepers.
Participants who were randomly assigned to some or only exercise maintenance achieved sustained sleep quality improvements from diet by one global score point (P = .02), the researchers reported. Maintenance with liraglutide had no significant effect on any sleep measure.
Adults with obesity who lost weight while dieting struggled to maintain their weight loss if they slept less than 6 hours per night.