Exercise in a polluted cityis it beneficial or harmful? The benefits associated with physical activity most often exceed the risks associated with pollution, according to a study led by researchers at the University of Cambridge. Their work is published in the journal preventive medicine. Last October, the Institut de Veille Sanitaire (InVS) already reported that cycling in the city was good for your health, despite the pollution.
Up to 1h30 of cycling per day in the most polluted cities
The researchers here examined the risk-benefit balance between physical activity and exposure to air pollution. To do this, they modeled different scenarios of active journeys (from 0 to 16 hours of walking or cycling per day) in different cases of fine particle pollution called PM2.5 (from 5 to 200 micrograms (µg) per cubic meter). They then looked at the mortality risks for each case.
The first result is good news. On average, the urban landscape contains 22 µg of fine particles per cubic meter of air (the limit set by the World Health Organization being 20 µg per cubic meter). And, in this case, the benefits of physical activity far outweigh the risks associated with pollution, within a certain limit: “a small minority of riders engaging in unusually high levels of active commuting (e.g. bike couriers) […] may be exposed to such air pollution that it negates the benefits of the activity“, warn the authors in their publication. And when pollution rises to 100 µg of fine particles per cubic meter, it is better not to exceed 1h30 of cycling or 10h of walking per day. This is the case in the cities the most polluted in India and China.
Fight sedentary lifestyle
In moderately polluted environments, moderate daily physical activity would therefore provide health benefits by reducing early mortality risks related to sedentary lifestyle : overweight, obesity, diabetes, cancers and cardiovascular diseases.
Another undeniable advantage of traveling on foot or by bicycle: that of leaving the car in the garage. A winning move for the wallet but also for the reduction of air pollution.
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