Regular exercise, even performed in areas with polluted air, may lower the risk of death from natural causes, according to a study published on Monday.
The researchers wanted to understand the effects of regular exercise and long-term exposure to fine particle matter on the risk of death from natural causes.
Their research, published in Canadian Medical Association Journal, included 384,130 adults in Taiwan who were followed for over 15 years from 2001 to 2016.
The researchers found that a high level of habitual exercise and a low level of exposure to air pollution was associated with lower risk of death from natural causes.
On the other hand, a low level of habitual exercise and a high level of exposure was associated with higher risk of death, according to the researchers.
"Habitual exercise reduces the risk of death regardless of exposure to air pollution, and air pollution generally increases the risk of death regardless of habitual exercise," said Xiang Qian Lao, from the Chinese University of Hong Kong.
"Thus, habitual exercise should be promoted as a health improvement strategy, even for people residing in relatively polluted areas," Lao said.
The research adds to several other smaller studies conducted in the US, Denmark and Hong Kong which found that regular exercise, even in polluted areas, is beneficial.
"Further studies in areas with more severe air pollution are required to examine the applicability of our findings," the authors wrote in the study.
"Our study reinforces the importance of air pollution mitigation, such as to reduce the harmful effects of air pollution and maximise the beneficial effects of regular exercise," they said.
Researchers from the University of Sydney in Australia, who were not involved in the study, noted in a related commentary that physical inactivity and air pollution should be considered as "syndemics" as together they influence behaviour and health outcomes.
Recommendations for safe exercise in polluted areas, such as indoor exercise, and avoiding walking and biking on congested roads, can contribute to inequalities as people of lower socioeconomic status often lack these options.
"Risk reduction approaches that do not address the root causes of noncommunicable diseases could exacerbate health inequalities,” wrote commentary authors Ding Ding and Mona Elbarbary.
"People should not be forced to choose between physical activity and air pollution," they said.
The authors explained that both physical inactivity and air pollution have detrimental effects on health, adding active lifestyle should not be at the cost of compromised health from air pollution.
Addressing both major public health issues through synergistic, upstream, system-level approaches would lead to long-term health benefits for humans and the planet, they added.