Regular exercise key to fighting high blood pressure even in air polluted areas

By Angela Betsaida B. Laguipo, BSNJul 20 2020

Hypertension is a significant risk factor for potentially fatal diseases, and controlling it can reduce the risk of death and other long-term complications.

Now, a team of researchers has found that regular physical activity or exercise can combat hypertension even in areas where there are high levels of air pollution.

Published in the journal Circulation, the study shows that regular physical activity is recommended to prevent hypertension, and it also highlights the importance of reducing air pollution for hypertension prevention.

Hypertension and physical activity

Hypertension is a condition wherein the blood pressure is too high. Blood pressure is the force that the blood exerts against the walls of the blood vessels. The pressure depends on the resistance of the blood vessels and how hard the heart needs to work.

High blood pressure is a primary risk factor for cardiovascular disease, which includes heart attack, heart failure, stroke, and aneurysm, which are potentially fatal.

Hypertension or high blood pressure is a common condition that affects more than one billion adults across the globe. It is the leading risk factor for cardiovascular disease and death. Elevated systolic blood pressure (SBP) contributed to roughly 10.5 million deaths in 2016.

To address the skyrocketing cases of hypertension, the World Health Organization (WHO) proposed a global target to reduce hypertension prevalence by 25% by 2025. One of the measures includes a physical activity to reduce the risk of hypertension and, consequently, cardiovascular disease and mortality.

Air pollution

Air pollution levels remain dangerously high in several parts of the world. The WHO reports that 9 in 10 people breathe air containing high levels of pollutants. Each year, 7 million people die due to ambient or outdoor and household pollution.

Previous studies have shown that air pollution increases the risk of hypertension. These studies have also shown that when a person exercises, the ventilation rate increases, which would mean there is an increased intake of air pollutants that may worsen the adverse health effects caused by air pollution. Further, some studies pointed out that exercising in areas that are polluted may override its benefits.

Health guidelines are needed in regions where there are high levels of air pollution, whether they can benefit from regular exercise.

Study: Independent and Opposing Associations of Habitual Exercise and Chronic PM2.5 Exposures on Hypertension Incidence. Image Credit: lzf / Shutterstock

The study

To arrive at their findings, the team investigated the links among habitual physical activity, long-term exposure to ambient fine particulate matter (PM2.5) with hypertension, or high blood pressure in adults in Taiwan. The country's annual PM2.5 concentrations are higher than the limit recommended by the WHO guideline.

They recruited more than 140,000 people who are more than 18 years old and had no history of hypertension. The team measured the PM2.5 exposure in each of the participant's address using a satellite data-based spatiotemporal model. The team then collected data using a self-administered questionnaire.

Findings show that people who regularly exercise or who are highly active and exposed to low levels of pollution had a reduced risk of developing high blood pressure. On the other hand, people who were inactive and exposed to highly polluted air had an increased risk of hypertension.

Also, each PM2.5 level increase was tied to a 38-percent increase in the risk of hypertension, and every increase in physical activity causes a 6-percent lower risk of hypertension. The findings show that reducing air pollution is more effective in preventing high blood pressure.

However, the study also highlights that regular physical activity lowers the risk of high blood pressure, regardless of the pollution level. This means that people who exercise more in polluted areas still benefit from the lower risk of hypertension. Those who are active or exercised moderately had a 4-percent lower risk of hypertension compared with those who did not exercise. Further, people who had to do high-level exercise had a 13-percent lower risk of hypertension than those who do not exercise.

"Extended outdoor activity in urban areas increases the intake of air pollutants, which can worsen the harmful health effects of air pollution," Dr. Xiang Qian Lao, Ph.D., an associate professor at the Jockey Club School of Public Health and Primary Care at The Chinese University of Hong Kong in Shatin, Hong Kong, 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," they added.

The team emphasizes that the findings cannot be generalized for other populations since the study was conducted in Taiwan. It is important to conduct studies in areas with higher air pollution exposure. Also, the team did not distinguish between outdoor and indoor physical activity.