Could climbing harm your health? New research has found that air pollution in indoor climbing gyms could be "among the highest ever documented worldwide," thanks to a high concentration of potentially harmful chemicals in climbing shoes.
In a study published in the ACS ES&T Air journal, researchers from the University of Vienna and EPFL Lausanne collected air samples from bouldering gyms in Austria, France, Spain, and Switzerland, where they were surprised to find dangerously high pollution levels, comparable to the busy roads of megacities. Levels were at their highest in smaller, confined climbing venues.
The culprit? Chemical additives in rubber shoe soles, released when climbers take to the wall. Researchers tested 30 pairs of climbing shoes and found many of the same additives present in car tires, some of which could be harmful to humans.
The substances - known as rubber derived compounds (RDCs) were found on the soles of climbing shoes, aerosol matter (particles in the air), on foot and hand holds and settled dust.
Researchers said the particles in the air were likely partly caused by climbers' shoes rubbing against the climbing wall, but were also being caused by climbers brushing the resulting dust off foot and hand holds, causing them to be air borne, where climbers and climbing gym staff could breathe them in.
While the exact effects of these additives are unclear, co-author Thilo Hofmann is calling on manufacturers to switch to less potentially harmful materials.
"These substances do not belong in the air we breathe," he told Phys.org.
"It makes sense to act before we know all the details about the risks, especially with regard to sensitive groups such as children.
"It is essential to switch to sole materials with fewer harmful substances."
Climbing is an increasingly popular sport in the US and abroad. More than six million Americans participated in some indoor climbing activity in 2024, and there are now over 500 climbing gyms in the States.
Climbing is generally thought to have a positive impact on your mental and physical health.
Research published in 2018 by the National Library of Medicine found that regular climbers benefit from a significantly improved range of motion and VO2max (the maximum rate at which your body uses oxygen) compared to non-climbers. Other studies have focused on the growing sport's mental health benefits.
- The best climbing shoes: get a grip both indoors and out
- The best climbing films: 10 great movies about incredible mountain adventures
