\n\tEngland<\/p>\n
\n\tResearch from University College London (UCL) indicates that long-term exposure to polluted air can considerably reduce the health benefits of regular exercise.<\/p>\n
\n\tThe study analysed data from over 1.5 million adults tracked for more than ten years across countries including the UK, Taiwan, China, Denmark, and the US.<\/p>\n
\n\tResearchers discovered that while regular physical activity still offers protective effects against overall mortality, cancer, and heart disease, these benefits are diminished for individuals living in areas with high pollution levels.<\/p>\n
\n\tThe team focused on fine particulate matter, or PM2.5, tiny particles less than 2.5 micrometres in diameter that can lodge in the lungs and enter the bloodstream. They found that exercise benefits were significantly weakened when annual average PM2.5 levels exceeded 25 micrograms per cubic metre (\u00b5g\/m\u00b3)\u2014a threshold exceeded by nearly 46% of the global population.<\/p>\n
\n\tProfessor Po-Wen Ku of National Chung Hsing University, Taiwan, emphasized, \u201cExercise remains beneficial even in polluted environments. But improving air quality can substantially enhance these health gains.\u201d<\/p>\n
\n\tUCL co-author Professor Andrew Steptoe added, \u201cToxic air can partially block exercise benefits, though it does not eliminate them entirely. This underscores the importance of addressing fine particle pollution to support healthy ageing alongside physical activity.\u201d<\/p>\n
\n\tThe research combined findings from seven studies, including three unpublished ones, and re-analysed raw participant-level data from three studies. The overall analysis revealed that individuals who engaged in at least 2.5 hours of moderate to vigorous exercise weekly had a 30% lower risk of mortality compared to those who did not meet this threshold.<\/p>\n
\n\tHowever, for participants in high PM2.5 areas (above 25 \u00b5g\/m\u00b3), the risk reduction fell to 12\u201315%. At levels above 35 \u00b5g\/m\u00b3, exercise benefits weakened further, particularly regarding cancer mortality. Around 36% of the global population live in regions exceeding this higher threshold.<\/p>\n
\n\tIn the UK, average yearly PM2.5 levels were about 10 \u00b5g\/m\u00b3, below the critical thresholds, though winter pollution spikes in some cities can surpass 25 \u00b5g\/m\u00b3.<\/p>\n
\n\tProfessor Paola Zaninotto of UCL advised, \u201cWe don\u2019t want to discourage outdoor exercise. Checking air quality, choosing cleaner routes, or reducing intensity on polluted days can help maintain exercise benefits.\u201d<\/p>\n
\n\tThe authors noted that the study was mostly conducted in high-income countries, so results may differ in low-income regions with higher pollution levels, often exceeding 50 \u00b5g\/m\u00b3. Limitations also included limited data on indoor air quality and participants\u2019 diets.<\/p>\n