Physical activity and cardiometabolic health across an extreme lifestyle gradient.

Background and objectives: Cardiometabolic health in many small-scale subsistence populations has been shown to be substantially better than populations living in industrialized, urban environments. This disparity is often partially attributed to the characteristically high levels of physical activity observed in non-industrialized societies, yet it remains unclear how much of the difference in cardiometabolic health between non-industrialized and industrialized populations is due specifically to physical activity rather than to other lifestyle factors that covary with industrialization. Methodology: To address this question, we collected objective data on physical activity (as characterized by daily step counts, time spent inactive, and intensity gradient, among other measures), cardiometabolic biomarker profiles (16 measures: anthropometrics, blood lipids, blood pressure, obesity, hypertension, pre-diabetes, and diabetes), and detailed lifestyle information from 1075 Orang Asli adults in Peninsular Malaysia, who span an exceptionally wide lifestyle gradient from small-scale subsistence communities to urban, industrialized settings. Results: More urban and market-integrated lifestyles were associated with marked reductions in physical activity, particularly among older individuals, and with poorer cardiometabolic health. At the individual level, greater physical activity was directly associated with better cardiometabolic health. However, physical activity accounted for only a small portion of urbanization's association with cardiometabolic health, indicating that other industrialization-related factors play substantial roles in shaping health outcomes. Conclusions and implications: These findings suggest that declining physical activity represents an evolutionarily novel challenge that exacerbates the burden of cardiometabolic disease, especially among older adults, in contemporary industrialized environments.