Mixed
Shorter objectively measured sleep duration is associated with higher BMI in cross-sectional analysis, but sleep duration does not predict longitudinal weight gain over 5 years.
Prioritizing sleep is healthy, but this study suggests that for many adults, simply extending sleep duration may not lead to weight loss. If you are struggling with weight, check for sleep-disordered breathing (like snoring) and address socioeconomic stressors, as these may be stronger drivers of the sleep-BMI link than sleep duration alone.
The authors confirmed a cross-sectional association between sleep duration and BMI using objective sleep measures, but they did not find that sleep predicted change in BMI.
Why this rating
High-quality objective measurement (actigraphy) and large cohort (n=612), but observational design limits causal inference regarding weight change.
Source
Cross-sectional and Longitudinal Associations Between Objectively Measured Sleep Duration and Body Mass Index: The CARDIA Sleep Study
Diane S. Lauderdale et al. · American Journal of Epidemiology · 2009
DOI 10.1093/aje/kwp230
Related findings · Mixed
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