A new study has shown that women's running in a marathon is compromised by poor air quality, but the same doesn't hold true for men.
In the study, Virginia Tech civil and environmental engineer Linsey Marr evaluated marathon race results, weather data, and air pollutant concentrations in seven marathons over a period of eight to 28 years.
The researchers compared the top three male and female finishing times with the course record and contrasted with air pollutant levels, taking high temperatures that were detrimental to performance into consideration.
Marr said higher levels of particles in the air were associated with slower running times for women, while men were not significantly affected.
She added that the difference could be due to the smaller size of women's tracheas, which makes it easier for certain particles to deposit there and possibly to cause irritation.
"Although pollution levels in these marathons rarely exceeded national standards for air quality, performance was still affected," said Marr.
Her studies were conducted where major U.S. marathons are located, such as New York, Boston, and Los Angeles, where pollution tends to be highest.
She said that although the person might not be significantly impacted by low-yet-still-acceptable air quality, marathoners are atypical because of their breathing patterns.
"Previous research has shown that during a race, marathon runners inhale and exhale about the same volume of air as a sedentary person would over the course of two full days. Therefore, runners are exposed to much greater amounts of pollutants than under typical breathing conditions," said Marr.
Particulate matter appeared to be the only performance-altering factor in air quality, with carbon monoxide, ozone, nitrogen dioxide and sulfur dioxide levels not impacting race times.
The study appears in the official journal of the American College of Sports Medicine, Medicine and Science in Sports and Exercise.