Abstract Background

Physical activity (PA) interventions play a critical role in addressing obesity and its associated health risks. Understanding their long-term effectiveness, particularly across diverse economic contexts, is essential for designing sustainable and scalable strategies. This systematic review aimed to evaluate the long-term effectiveness of PA interventions implemented in low, middle, and high income countries (LMICs and HICs), identify key components contributing to their success.
Methods

Studies were included if they assessed PA interventions with follow-up periods of at least 12 months. A total of 27 studies from diverse countries met the inclusion criteria, encompassing 33 distinct strategies. Data were extracted on intervention components, follow-up duration, PA outcomes, and obesity-related measures. The studies were categorised by economic context, with a focus on comparing effectiveness across income groups.
Results

PA interventions demonstrated significant long-term effectiveness across all economic settings. In HICs, multicomponent interventions, such as those involving physician-led counselling, tailored exercise regimens, and fitness testing, were highly effective, showing improvements in weekly energy expenditure and physical fitness of up to 15%. Studies from MICs, like Mexico, highlighted the effectiveness of culturally tailored approaches, such as integrated care for older adults, in enhancing PA adherence despite resource constraints. LMICs, particularly China, leveraged culturally embedded and community-driven practices, such as tai chi and baduanjin, achieving comparable outcomes to HIC interventions in terms of PA adherence and fitness improvements.

However, sustainability of intervention effects varied. Robust maintenance strategies, including booster sessions and ongoing support, contributed to stable long-term outcomes in studies from HICs. Conversely, LMIC interventions often lacked extended follow-up, limiting their ability to evaluate sustained effectiveness. The interventions were consistently associated with reductions in obesity-related risk factors, including BMI and metabolic health improvements.
Conclusion

This review highlights the effectiveness of culturally sensitive and resource-adapted PA interventions in sustaining long-term behaviour change and reducing obesity-related risks across economic contexts. Future research should prioritise consistent monitoring, extended follow-up, and the inclusion of underrepresented LMIC regions to enhance the global applicability and scalability of PA interventions. Addressing these gaps is crucial for combating obesity and promoting public health worldwide.