Reducing nightly sleep by about 1.5 hours for 6 weeks may lead to modest weight gain among adults at elevated cardiometabolic risk, according to a pooled analysis of two randomized crossover trials.
The trials involved 95 adult participants aged 20 years or older at elevated cardiometabolic risk who habitually slept at least 7 hours per night. Researchers assigned the participants to complete two 6-week outpatient intervention periods: one maintaining adequate sleep of at least 7 hours per night and one involving sleep restriction achieved by delaying bedtime by about 1.5 hours per night. The intervention periods were separated by a 4- to 6-week washout interval. Sleep was monitored with wrist actigraphy and sleep diaries. The primary outcomes were body weight, waist circumference, and magnetic resonance imaging–derived body composition; while secondary outcomes included fasting appetite–related hormones, sedentary behavior, moderate-to-vigorous physical activity, and total daily energy expenditure.
Nightly sleep duration was reduced by an average of 78 minutes during the sleep restriction period. Compared with adequate sleep, sleep restriction was associated with a mean increase of 0.45 kg in body weight, 0.52 cm in waist circumference, and 0.56 L in whole-body volume. The researchers also noted higher fasting leptin concentrations and found that the participants spent about 17 more minutes per day engaged in sedentary behavior during sleep restriction.
The researchers did not observe statistically significant differences in the proportion of whole-body, visceral, or subcutaneous adipose tissue; skeletal muscle; fasting glucagon-like peptide-1 or ghrelin levels; moderate-to-vigorous physical activity; or total daily energy expenditure. Exploratory subgroup analyses suggested generally similar patterns among men, premenopausal women, and postmenopausal women, although the study was not powered to formally compare these groups.
The study had several limitations. The 6-week intervention may have been too brief to detect meaningful changes in body composition, the relatively small sample limited subgroup analyses and generalizability, and fasting metabolic measurements did not capture hormonal changes across the full 24-hour cycle.
Overall, the findings suggested that sustained moderate sleep restriction may contribute to modest weight gain among those at elevated cardiometabolic risk; however, longer-term studies are needed to determine whether these changes may result in measurable alterations in body composition.
"The increase in body weight of about 0.5 kg attributable to SR is equivalent to the average annual weight change among young to middle-aged adults and provides causal evidence for a role of mildly insufficient sleep in the risk for weight gain," wrote lead study author Faris M. Zuraikat, PhD, of the Division of General Medicine in the Department of Medicine at the Columbia University Irving Medical Center, and colleagues.
The study was funded by the National Institutes of Health and the American Heart Association. Full disclosures of the study authors can be found in the study.
Source: Annals of Internal Medicine