Does Daily Moderate-to-Vigorous Physical Activity Affect Glycemic Control Equally Across Populations? Insights From NHANES 2005–2006

Current physical activity (PA) guidelines for chronic disease management (e.g., diabetes) are based on population averages and may not reflect physiological differences across racial/ethnic groups. This study investigates whether the association between PA and glycemic control varies among Non-Hispanic White (NHW), Non-Hispanic Black (NHB), and Mexican American (MA) adults. We analyzed weighted NHANES 2005-2006 data in adults aged ≥20 (n = 2354 unweighted). PA was measured via accelerometer (≥10 hours/day, 4-7 days) and glycemic control was assessed using HbA1c, categorized as normal (<5.7%), prediabetes (5.7%–<6.5%), and diabetes (≥6.5%). Questionnaire-reported sleep time was integrated with accelerometer-derived sedentary behavior (SB), light-intensity physical activity (LIPA), and moderate/vigorous physical activity (MVPA) to represent a 24-hour time-use composition. Weighted multivariate isotemporal compositional regression models were then conducted to estimate HbA1c across activity categories adjusting for confounders and stratified by race/ethnicity. Mean HbA1c differed by racial/ethnic groups: NHW (5.41%), NHB (5.78%), and MA (5.61%) ( P < .01). At 30 min/day of MVPA, HbA1c was lower in NHW (5.28%) compared to NHB (5.62%) and MA (5.56%) ( P < .01). Similar trends were observed at 20 and 0 min/day ( P < .01). MVPA is associated with improved glycemic control, but the benefits vary by race/ethnicity. Findings suggest that PA benefits differ by race/ethnicity, indicating a need for more tailored guidelines incorporating additional lifestyle and contextual factors.