Regular physical activity, even in areas with moderate to high levels of traffic pollution, is still effective in reducing the risk of first and recurrent myocardial infarction (MI), according to a study published online July 18 in the Journal of the American Heart Association.
European researchers, led by Nadine J. Kubesch, PhD, MPH, of the University of Copenhagen in Denmark, sought to examine the effects of physical activity on MI. They also looked to see if potential benefits are reduced by exposure to traffic-related air pollution.
“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,” said Kubesch, in a prepared statement issued by the American Heart Association. “Currently there is little data on whether poor air quality cancels out the protective benefits of physical activity in preventing heart attacks.”
More than 50,000 individuals aged 50-65 were part of the final cohort. Researchers collected information on smoking and alcohol habits, diet, education, disease and medications at baseline.
Researchers included cycling, gardening, sports and walking as physical activity in the analysis. The researchers used national traffic pollution monitoring data to determine the amount of nitrogen dioxide (NO2) that corresponded with each participant’s home address.
At baseline, almost 97 percent of study subjects did not have MI or a history of MI. During the 17-year follow-up, researchers found 2,936 participants developed MI. Of the 1,233 participants with MI before baseline, 324 had a recurring MI.
Kubesch and colleagues found higher levels of traffic pollution were associated with more incidences of MI, but the risk of MI was lower among physically active individuals.
The researchers found that moderate cycling for at least four hours decreased the risk of recurrent MI by 31 percent. MI risk was reduced by 58 percent when all types of physical activity were adhered to for the same time period, regardless of air quality.
Additionally, study subjects who participated in sports had a 15 percent lower rate of initial MI. Study subjects who cycled saw risk for MI reduced by 9 percent, regardless of air quality.
“Our study shows that physical activity even during exposure to air pollution, in cities with levels similar to those in Copenhagen, can reduce the risk of heart attack,” Kubesch said. “Our research supports existing evidence that even moderate levels of regular physical activity, such as active commuting, are sufficiently intense to get these health benefits.
As a senior news writer for TriMed, Subrata covers cardiology, clinical innovation and healthcare business. She has a master’s degree in communication management and 12 years of experience in journalism and public relations.