In a new study, researchers found people who regularly exercise tend to have a lower risk of high blood pressure, even if they live in areas where air pollution is relatively high.
They found that while high physical activity combined with lower air pollution exposure was linked to lower risk of high blood pressure, physical activity continued to have a protective effect even when people were exposed to high pollution levels.
The research was conducted by a team at The Chinese University of Hong Kong.
The risk-benefit link between air pollution and physical activity is an important public concern because more than 91% of people worldwide live in areas where air quality does not meet World Health Organization (WHO) guidelines.
Extended outdoor activity in urban areas increases the intake of air pollutants, which can worsen the harmful health effects of air pollution.
In the study, the researchers examined more than 140,000 non-hypertensive adults in Taiwan and followed them for an average of 5 years.
They classified the level of exposure to fine particulate matter (PM2.5) as low, moderate, and high. PM2.5 is the most commonly used indicator of air pollution. High blood pressure was defined as 140/90 mm Hg.
The American Heart Association/American College of Cardiology 2017 Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults defines high blood pressure as 130/80 mm Hg.
The researchers found that overall, people who are highly active and exposed to low levels of pollution had a lower risk of developing high blood pressure.
People who were inactive and exposed to highly polluted air had a higher high blood pressure risk.
Each increase in PM2.5 level was associated with a 38% increase in the risk of incident hypertension, whereas each increase in physical activity level leads to a 6% lower risk of hypertension.
This suggests that reducing air pollution is more effective in preventing high blood pressure.
The benefits of regular physical activity held up regardless of the pollution level. People who exercised moderately had a 4% lower risk of high blood pressure than those who didn’t exercise.
People who exercised at a high level had a 13% lower risk of high blood pressure than the non-exercisers.
The findings indicate that regular physical activity is a safe approach for people living in relatively polluted regions to prevent high blood pressure.
The team says exercise should be promoted even in polluted areas. The findings also put a spotlight on how strongly pollution can impact blood pressure, and how important it is to control pollution levels to prevent high blood pressure.
One author of the study is Xiang Qian Lao, Ph.D., an associate professor at the Jockey Club School of Public Health and Primary Care.
The study is published in Circulation.
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