Urban running with a smartwatch is great but don’t ignore pollution
Running is one of the simplest ways to stay healthy, but in polluted cities, it’s not always as beneficial as it seems. While smartwatches and fitness trackers help you track your health, they often overlook the crucial factor of air quality.
In a study a few year ago, an international team of scientists modelled the health benefits of cycling and walking against the negative effects of air pollution. They looked at air quality through average annual levels of PM2.5s and calculated a tipping point – the length of time after which exercising becomes harmful as a result of inhaling fine particulates. Researchers found that in a number of cities such as Delhi in India or Zabol in Iran, cycling for just 30 minutes can start to damage your health!
“If you are beyond the break-even point, you may be doing yourself more harm than good,” said Audrey de Nazelle, a lecturer at Imperial College’s Centre for Environmental Policy, and one of the authors of the study.
When air quality makes exercise harmful
Air pollution in major cities is of increasing concern. According to the World Health Organization (WHO), more than 80% of people living in urban areas that monitor air pollution are exposed to air quality levels that exceed the WHO limit of 10μg/m3. While all regions of the world are affected, populations in low-income cities are at most risk.
Short-term air pollution can aggravate the medical conditions of individuals with asthma and emphysema. Long-term health effects can include chronic respiratory disease, lung cancer, heart disease, and even damage to the brain, nerves, liver, or kidneys.
The good news is that only 1% of cities in the world have consistent high levels of air pollution that cycling or walking could be detrimental to a person’s health. The study found people in western cities such as New York (9 μg/m3), Chicago (12μg/m3), Los Angeles (11μg/m3), London (15μg/m3) or Paris (18μg/m3), would never reach the point where air pollution’s negatives outweigh exercise’s positives in the long term. For info the global average urban background PM concentration is 22 μg/m3.
You have to go above 100 μg/m3 to get into the detrimental effects. At that level harms would exceed benefits after 1 hour 30 minutes of cycling per day or more than 10 hours of walking per day!
How the Air Quality Index can guide you
What the research does not take into account, however, is the occasional spike in air pollution levels. In London for example, the annual average PM2.5 pollution is estimated at 15μg/m3 by the WHO. But in certain months, the British capital’s pollution levels can rise in excess of 100μg/m3.
This only goes to show the importance of monitoring pollution levels if you live in a urban area, even if the city is generally considered to be safe. Particularly if you have a habit of cycling to and from work every day.
An easy way to keep an eye on things is the Air Quality Index (AQI). It offers a clear guide. AQI measures air quality on a scale from 0 to 500, with higher numbers indicating worse pollution. Each range of AQI values corresponds to a level of health concern:
AQI Range | Description | Health Implications | Exercise Advice | PM2.5 Equivalent (μg/m³) |
|---|---|---|---|---|
0–50 | Good | Air quality is considered safe for everyone. | Outdoor exercise is safe for all. | 0–12 |
51–100 | Moderate | Air quality is acceptable, but sensitive individuals may notice mild effects. | Sensitive groups should monitor symptoms during outdoor exercise. | 12.1–35.4 |
101–150 | Unhealthy for Sensitive Groups | Sensitive individuals may experience respiratory irritation. | Sensitive groups should limit prolonged outdoor exertion. | 35.5–55.4 |
151–200 | Unhealthy | Everyone may begin to feel adverse health effects, especially with prolonged exposure. | Limit outdoor exercise; consider alternatives like indoor activities. | 55.5–150.4 |
201–300 | Very Unhealthy | Health risks increase significantly for everyone. | Avoid outdoor exercise entirely. | 150.5–250.4 |
301+ | Hazardous | Serious health risks for everyone. | Stay indoors; avoid outdoor activity completely. | 250.5+ |
Our takeaway
There you have it folks. Running and exercise in general may not always be as healthy as it seems.
In periods where you suspect there may be detrimental air quality, keep an eye on the AQI index. If you must exercise in less-than-ideal conditions, time your exercise to coincide with periods of better air quality—such as early mornings or after rain. Additionally, tools like N95 masks or exercising indoors during high pollution days can help mitigate exposure risks.
We haven’t seen fitness trackers with built-in air quality features just yet, but there are plenty of personal environmental monitors. On top of that, some smartwatches and sports watches, like those from Apple and Garmin, let you install air quality monitoring apps to keep tabs on the air you’re breathing. Exercising might be good for your health, but don’t let poor air quality take that away from you.
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