Polluted air quietly erases the benefits of exercise

Long-term inhalation of toxic air appears to dull the protective power of regular workouts, according to a massive global study spanning more than a decade and over a million adults. While exercise still helps people live longer, its benefits shrink dramatically in regions with heavy fine particle pollution—especially above key PM2.5 thresholds common in many parts of the world. The researchers emphasize that outdoor activity shouldn’t stop, but better air quality could unlock far greater health gains.