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Regular physical activity reduces the risk of a heart attack, even when it occurs in polluted air, according to a new study.
Breathing in Smog
I think most people who regularly run or cycle in a busy city wonder at times: “Am I doing the right thing by being so active in this air?” Especially when, at the end of a tough workout, you’re gasping for breath as a thick diesel truck drives by. Being outside means more exposure to the air, and being active means you have to breathe more of it.
Physical activity reduces the risk of cardiovascular disease, but air pollution actually increases the risk of heart and lung diseases. According to a team of Danish, German, and Spanish researchers, there was little information available to clearly determine whether poor air quality negates the positive effects of activity. It was their task to change that. They published their findings in the
Journal of the American Heart Association [1].
“Activity Remains Healthy Even in Polluted Air”
For their study, they evaluated the amount of outdoor activity such as sports, but also cycling, walking, and gardening. They compared this with data on the intake of nitrogen dioxide from traffic-polluted air. Finally, they looked at how often heart attacks occurred. They had this data from over 50,000 adults aged 50 to 65. Over a period of approximately 17.5 years, there were 2,936 first heart attacks and 324 recurrent heart attacks. To estimate exposure to polluted air, national data on traffic pollution at the participants’ addresses was used.
These were some of their conclusions:
- Higher levels of air pollution were associated with more heart attacks. The risk of a first heart attack was found to be 17 percent higher. The risk of a recurrent heart attack was 39 percent higher. However, the risk was lower in physically active participants.
- Four hours of physical activity per week (a combination of all four activities) reduced the risk of recurrent heart attacks by 58 percent. Regardless of air quality.
- People who exercise outdoors had a 15 percent lower risk of a first heart attack. Cyclists had a 9 percent lower risk of a first heart attack. In both cases, this was again regardless of air quality.
- The average exposure to nitrogen dioxide in people with a heart attack (first or recurrent) was less than half (18.9 μg/m3) of the EU guideline for exposure (50 μg/m3).
Keep on Running
The researchers therefore conclude that even in cities with heavy traffic and air pollution, it still pays to be active. You don’t even have to be particularly active for that.
You could also conclude that the EU guideline may need to be sharpened a bit.
References
- Nadine J. Kubesch, Jeanette Therming Jørgensen, Barbara Hoffmann, Steffen Loft, Mark J. Nieuwenhuijsen, Ole Raaschou‐Nielsen, Marie Pedersen, Ole Hertel, Kim Overvad, Anne Tjønneland, Eva Prescot, Zorana J. Andersen. Effects of Leisure‐Time and Transport‐Related Physical Activities on the Risk of Incident and Recurrent Myocardial Infarction and Interaction With Traffic‐Related Air Pollution: A Cohort Study. Journal of the American Heart Association, 2018; 7 (15): e009554
- https://www.ahajournals.org/doi/10.1161/JAHA.118.009554
