A major international study has revealed that the positive effects of regular exercise are significantly reduced in areas with high levels of air pollution. Researchers tracked over 1.5 million adults across several countries for more than ten years, finding that the health benefits of physical activity dropped by nearly half when participants were exposed to polluted air. The findings, published in a leading medical journal, highlight the impact of environmental factors on personal health and fitness outcomes. Experts suggest that people living in polluted areas take extra precautions when exercising outdoors to maximize the benefits of their workouts.