Here’s a very common expat question: is riding a bike in a city helping or harming your health? Fortunately, someone researched this exact question and now we can breathe with some relief, as the verdict is in: biking is beneficial.
The article was just published in Environmental Health Perspectives journal and is an essential read for those bikers out there, or the many fence-sitters a bit scared of Beijing’s streets and air. The paper, from a Netherlands group, reviewed all the current literature and data from multiple cities around the world and came up with some very encouraging figures:
For the individuals who shift from car to bicycle, we estimated that beneficial effects of increased physical activity are substantially larger (3 – 14 months gained) than the potential mortality effect of increased inhaled air pollution doses (0.8 – 40 days lost) and the increase in traffic accidents (5 – 9 days lost). Societal benefits are even larger due to a modest reduction in air pollution and greenhouse gas emissions and traffic accidents.
Conclusions: On average, the estimated health benefits of cycling were substantially larger than the risks relative to car driving for individuals shifting mode of transport.
The article has many good points, for example by noting that car drivers actually breathe in dirtier air than bikers, but bikers inhale more deeply. From the article:
Overall, air pollution exposures experienced by car drivers were modestly higher than those experienced by cyclists, with mean ratios of 1.16 for PM2.5, 1.01 for ultrafine particles and 1.65 for elemental carbon or soot. However, increased physical activity results in higher minute ventilation in cyclists than car drivers, with estimates from two Dutch studies reporting that the minute ventilation of cyclists was 2.3 times (van Wijnen et al. 1995) and 2.1 times (Zuurbier et al. 2009) higher than that of car drivers. Therefore, inhaled doses of fine particles and to a lesser extent elemental carbon may be higher in cyclists.
You can also read a news report about this article from Bloomberg: City Cycling Seems to Have More Upsides Than Down.
Biking To Work: Get All The Exercise You Need!
I think this is a very encouraging article, as it may sway some of you to bike more in Beijing as a form of exercise. Those few minutes each way on your commute can add up enough to give you the recommended heart-healthy exercise levels. Here are more details why:
In several physical activity studies, metabolic equivalent (MET) is used as an indicator of physical activity and the minimum goal should be in the range of 500 to 1000 MET·min·week. Leisure cycling or cycling to work (speed 15 km·hr) has a MET value of 4 and is characterized as a moderate activity. Hence, a person shifting from car to bike for a daily short distance of 7.5 km would meet the minimum recommendation (7.5 km / 15 km·hr = 30 minutes) for physical activity in 5 days (4 MET x 30 minutes x 5 days = 600 MET·min·week).
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