Sedentary Behaviour as a Global Health Threat: A Comprehensive Integration of NEAT, HEPA, and Exercise - A Narrative Review

Physical inactivity represents a global pandemic, contributing to approximately 5 million deaths annually and affecting nearly 1.8 billion adults worldwide. This narrtive review synthesizes current evidence on the continuum from inactivity to active living, examining three complementary frameworks: Health Enhancing Physical Activity (HEPA), Non Exercise Activity Thermogenesis (NEAT), and structured exercise. Drawing from landmark original studies, umbrella reviews, and longitudinal cohort data, we examine the dose response relationship between physical activity and health outcomes, the unique contributions of each activity domain, and practical strategies for clinical implementation. The evidence demonstrates that every increment of movement confers measurable health benefits, with the steepest risk reductions occurring when moving from complete inactivity to even minimal activity. A synergistic model integrating NEAT as a foundation, HEPA as a target, and structured exercise for optimization represents the most effective approach for population level health promotion.