The benefits of your daily run outweigh the risks of the particulate matter in the air, study finds
Regular exercise, even in areas with high air pollution, can lower your risk of early death from natural causes, according to a new study published in the Canadian Medical Association Journal (CMAJ).
Though your risk of early death rises with exposure to fine particulate matter (PM2.5) in the air, you can reduce it through exercise, regardless of your levels of exposure to PM2.5.
Wildfires account for half of overall hazardous air pollution in the western U.S., and up to a quarter of PM2.5 exposure in the U.S. in general.
To go out for a run or not to go out for a run? That’s a question many runners in the U.S. (and beyond) increasingly must ask as wildfires happen earlier and last longer, billowing particulate matter (PM2.5) clear across the nation. Sure, it creates a backdrop for stunning sunsets, but it also makes the air worrisome to breathe and negatively impacts health.
Though sucking in high levels of air pollution will never be good for you, new research shows that the benefits of exercising outweigh the risks of the bad air. The study, published in the Canadian Medical Association Journal (CMAJ), found that regular exercise, even when performed in areas with air pollution, can reduce the risk of early death from natural causes, compared to being sedentary.
Researchers examined the health records and activity levels of more than 384,000 adults living in Taiwan—where the annual air pollution levels of PM2.5 are 1.6 times higher than the World Health Organization-recommended limit—over a 15-year period from 2001 to 2016. The researchers looked at both levels of exposure to PM2.5, as well as the study participants’ activity levels.
In terms of pollution, exposure levels were based on the two-year average concentration in the year of a medical examination and in the previous year, and were broken into the following categories. (The concentration of an air pollutant is measured in μg/m3, or micrograms per cubic meter of air.)
Low: < 22.4 μg/m3
Moderate: 22.4–26.0 μg/m3
High: ≥ 26.0 μg/m3
PM2.5 is especially problematic for your health, according to the World Health Organization, because it can penetrate the lung barrier and enter your bloodstream. It raises the risk of developing cardiovascular and respiratory disease as well as cancer.
The participants’ activity levels were assigned to a category corresponding with their reported METs (metabolic equivalent for task):
Inactive (0 METs—the equivalent of sitting quietly)
Moderate (0 to 8.75 METs—runs at around a 12-minute mile pace or less)
High (greater than 8.75 METs—runs faster than a 12-minute mile pace)
In the end, those with both high levels of exercise and low levels of exposure to pollution fared best (no surprise there). But though risk of early death rises with pollution exposure, you can reduce it through exercise, regardless of the levels of PM2.5 exposure, says study author 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.
“For example, among the people with high PM2.5 exposure—compared to inactive, moderate, and high exercise—can reduce [early] death risk 16 percent and 33 percent [respectively],” Lao told Runner’s World.
Among those with moderate PM2.5 exposure, compared to inactive, those performing moderate and high exercise can reduce their early death risk 13 percent and 29 percent respectively. And among those with low PM2.5 exposure, those performing moderate and high levels of exercise can reduce their early death risk 19 percent and 41 percent respectively compared to their inactive peers.
That’s not to say you should ignore the U.S. Air Quality Index (AQI), which takes five major air pollutants—including PM2.5—into account and go bust out a long run when it’s code maroon (hazardous), but it’s reassuring to know that if you live in a place with increasingly imperfect air much of the year, your daily run still does your body good.
posted Saturday August 21st
by Runner’s World