Dose-response Relationship between Leisure-time Physical Activity and Metabolic Syndrome in Short Sleep US Adults: Evidence from a Nationwide Investigation.

Metabolic syndrome (MetS) and short sleep are prevalent health concerns in the United States, yet the relationship between leisure-time physical activity (LTPA) and MetS among individuals with short sleep duration remains unclear. This cross-sectional study analyzed data from 8999 US adults aged 20 years and older in the National Health and Nutrition Examination Survey (NHANES). Short sleep duration was defined as less than 7 hours per night, and MetS was diagnosed based on criteria from the American Endocrine Society and the American Society of Clinical Endocrinology. Weighted regression analyses revealed a significant inverse association between LTPA and MetS, with higher LTPA levels linked to lower MetS [OR (95% CI): 0.990 (0.984, 0.997), p = 0.003]. Participants who achieved the World Health Organization's recommended LTPA levels had a substantially lower MetS compared to those with no LTPA [OR (95% CI): 0.624 (0.527, 0.738), p = 0.001]. Stratified analyses showed that this protective effect varied across demographic subgroups, and a threshold effect was observed at 2000 MET-minutes per week, beyond which further LTPA did not significantly enhance protection against MetS. These findings highlight the importance of regular LTPA is negatively associated with MetS among individuals with inadequate sleep, emphasizing the need for targeted health promotion efforts in this population.