The Air At Your Gym Is Dirty. Filthy, Even

A new study found dangerous levels of carbon monoxide, carbon dioxide and even formaldehyde at gyms

If you were looking for an excuse not to go to the gym, this might just be it: the air there is dangerously dirty.

A new study has found that the air in indoor gyms is riddled with dangerous gases and chemicals, with levels so high they exceed safety standards for air quality.

Researchers from Portugal and Holland placed air quality monitors in gyms all over Lisbon for a month and what they found will make you want to hold your breath forever (but please don't do that, obvs).

The levels of dust, formaldehyde, and carbon dioxide were worst in confined spaces, for example aerobic studios, and at peak times, so after work and lunch hours.

The researchers put the dirty air down to poor ventilation, cleaning products and, ironically, gym-goers themselves. You see, the carbon dioxide problem is made worse by a large number of people breathing heavily, and therefore producing carbon dioxide, in a small space.

The research also rather helpfully pointed out that the gym is the last place that should have poor air quality because that's where people inhale the deepest. Carla Ramos, the lead author of the study, says: 'When we exercise, we take in more air with each breath and most of that air goes through the mouth, bypassing the natural filtration system in the nostrils. The pollutants go deeper into the lungs compared to resting situations.'

Rather than putting people off using the gym to exercise, Ramos hopes this study will be a wake-up call for the fitness industry to up their game when it comes to gym ventilation and cleanliness.

If you're worried about the state of your gym, speak to the manager. Or, go for a run in the great outdoors. Here are 10 reasons you should go running.