Regular physical activity lowers the risk of a heart attack, even when it happens in polluted air. This is revealed in a new study.
Breathing in Smog
I think most people who regularly (run) or cycle in a busy city have wondered at some point: “Is it good for me to be this active in this air?” Especially when you’re gasping for breath at the end of a tough workout while a thick diesel truck passes by. Being outdoors means more exposure to the air, and being active means you have to breathe more of it in. Physical activity reduces the risk of cardiovascular disease, but air pollution actually increases the risk of cardiovascular and lung diseases. According to a team of Danish, German, and Spanish researchers, there was little information available to clearly show whether poor air quality negates the positive effects of activity. It was up to them to change that. They published their results 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, as well as cycling, walking, and gardening. They compared this to data on the intake of nitrogen dioxide from polluted air due to traffic. Finally, they looked at how often heart attacks occurred. They had this data from over 50,000 adults aged 50 to 65 years old. Over a period of about 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. Here are 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 (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 chance of a first heart attack. Cyclists had a 9 percent lower chance 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 not even 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 could be set a bit more sharply.- 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
