A new study has found that the benefits of exercise may be significantly reduced for people living in polluted areas, even if they maintain a regular physical activity routine. While exercise is an effective way to improve mental health and reduce the risk of heart disease, ambient air quality may play a crucial role in determining the extent of these benefits.
Researchers from University College London analyzed data from over 1.5 million adults in the UK, Taiwan, China, Denmark, and the US, who were followed for more than a decade. They assessed the participants' levels of physical activity, along with their exposure to fine particulate matter known as PM2.5, which can penetrate the lungs and enter the bloodstream.
The study found that people who engaged in at least two and a half hours of moderate to vigorous exercise per week had a 30% lower risk of death compared to those who were inactive. However, this figure dropped to between 12% and 15% for those living in areas where pollution levels exceeded 25 micrograms of fine particulate matter per cubic meter.
It turns out that the health benefits of exercise are weakened even more in the most polluted areas, with the study indicating that when PM2.5 levels exceed the 35 micrograms per cubic meter threshold, the benefits of exercise in reducing the risk of cancer become "not strong".
About 46% of the world’s population lives in areas where pollution exceeds 25 micrograms, while 36% live in areas where the annual average of fine particulate matter is above 35 micrograms per cubic meter.
Professor Po-Wen Kuo, the lead researcher from National Chung-Hsing University in Taiwan, said the study clearly shows that exercise is still beneficial even in polluted environments, but improving air quality could "significantly boost health gains."
The team recommended checking air quality levels, choosing less polluted routes, and limiting physical activity on days with high levels of fine particulate matter.
Professor Andrew Steptoe of University College London said, "Toxic air can hinder the benefits of exercise, but it does not negate them," stressing that the findings represent further evidence of the significant health risks posed by fine particulate matter pollution.
The study was published in the journal BMC Medicine.
