People who live in polluted cities are more likely to suffer from cardiovascular disease (CVD) including arrhythmia, heart failure, heart attack, and stroke.
Air pollution increases the incidence of high blood pressure, one of the most important risk factors for CVD.
A study has found that individuals who live in areas with high levels of air pollution, but who exercise routinely, have normal blood pressure, suggesting physical activity even in polluted cities can prevent or reverse hypertension.
Habitual physical activity is simply the healthiest approach for lowering or even preventing high blood pressure.
At present over 91 percent of people live in places where World Health Organization (WHO) air quality guidelines are not met.
Air pollution is the biggest environmental risk to public health but physical activity can reduce the harm across different populations globally.
Dr iang Qian Lao, the study’s co-author, said:
“While we found that 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 message is that physical activity, even in polluted air, is an important high blood pressure prevention strategy.”
The team tracked 140,000 Taiwanese adults with healthy blood pressure for five years.
Participants, based on their physical activity levels, were divided into highly active, moderately active, and inactive.
Also, the level of exposure to fine particulate matter (PM2.5), a widely used indicator for air pollution, was categorised into high, moderate, and low in this study.
A reading of 140/90 mm Hg was considered high blood pressure whereas the American Heart Association guidelines on hypertension defines high blood pressure as 130/80 mm Hg.
This implies 50 percent of American adults have hypertension and are at increased risk of heart attack and stroke.
The findings were as follows:
- People with high activity who lived in areas with low levels of pollution were least likely to develop high blood pressure.
- Inactive people who lived in highly polluted air were most likely to have high blood pressure.
- For each increase in levels of PM2.5, the risk of having high blood pressure rose by 38 percent but by increasing the levels of physical activity the risk was reduced to 6 percent.
- High-intensity workouts reduced the risk of hypertension by 13 percent compared to inactivity.
Dr Lao said:
“This is the largest study to analyze the combined effects of air pollution and regular physical activity on high blood pressure.
Our findings indicate that regular physical activity is a safe approach for people living in relatively polluted regions to prevent high blood pressure.
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.”
The study was published in the journal Circulation (Guo et al., 2020).