Even in areas with moderate-to-high levels of traffic pollution, regular physical activity reduced the risk of first and recurrent heart attack, to new research in Journal of the American Heart Association, the Open Access Journal of the American Heart Association/American Stroke Association.
While exercise is known to reduce cardiovascular disease risk; pollution can increase the risk of cardiovascular disease, including heart attacks, asthma and chronic obstructive lung disease. Currently there is little data on whether poor air quality cancels out the protective benefits of physical activity in preventing heart attacks.—Nadine Kubesch, Ph.D., lead author and researcher at the University of Copenhagen in Denmark
Researchers in Denmark, Germany and Spain evaluated outdoor physical activity levels (sports, cycling, walking and gardening) and nitrogen dioxide (NO2 pollutant generated by traffic) exposure in 51,868 adults, age 50-65, comparing self-reported activities and lifestyle factors against heart attack. Over a 17.7-year period, there were 2,936 first heart attacks and 324 recurrent heart attacks.
To estimate average NO2 exposure, researchers used national traffic pollution monitoring data for each participants’ address and found:
Higher levels of were associated with more heart attacks, however, the risk was lower among those who were physically active.
Moderate cycling for four or more hours per week cut risk for recurrent heart attack by 31%; and there was a 58% reduction when all four types of physical activity (together totalling four hours per week or more) were combined, regardless of air quality.
Those who participated in sports had a 15% lower rate of initial heart attacks and there was a 9% risk reduction associated with cycling, regardless of air quality.
Compared to participants with low residential NO2 exposure, those in higher risk areas had a 17% increase risk in first heart attack and 39% for recurrent heart attack.
In participants who developed a heart attack (first or recurrent), the average NO2 exposure level was 18.9 microgramm per cubic meter air (μg/m3) with an overall average of 18.7 μg/m3, which is below the current NO2 European Union exposure guideline (50 μg/m3 over 24 hours).
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 (2018) “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 doi: