Delhi air pollution: Are marathon, cycling events in toxic air a good idea?

Doctors warn that running or cycling in Delhi's polluted air could trigger inflammation, heart irregularities, and breathing distress - and advise cancelling events when AQI exceeds 300

Delhi’s air is poison, so why are we still running marathons in it?

 

The air quality in Delhi-NCR has plunged into the “very poor” category, with AQI crossing 400 in several parts of the city. Yet, marathons and cycling events are still being held. As people push their physical limits in toxic air, doctors warn that these activities may be doing more harm than good.

What happens to the lungs and heart when you exercise in toxic air?

Your lungs are not just working, they are doing overtime. “We normally take around 20,000 breaths every day. But when you are jogging, sprinting, or pedalling, that number doesn’t just go up, each breath also gets deeper. Studies suggest your breathing volume can go up by four to six times,” says Dr Shivanshu Raj Goyal, Associate Director and Unit Head, Pulmonology, Respiratory and Sleep Medicine, Max Hospital, Gurugram.

 

 

That means you are pulling in four to six times more toxic air deep into your lungs, where particles like PM2.5 and PM1.0 can penetrate the blood vessels. According to Dr Goyal, these particles don’t just irritate, they set off a chain reaction of airway inflammation, oxidative stress, and even damage to the lining of blood vessels. Your heart feels it too, with increased blood pressure and irregular rhythms, and if you are already vulnerable, the risk of ischaemic events rises.

What are the immediate effects of pollution exposure on the body?

Even a single intense session in polluted air can cause measurable drops in lung function, such as reduced Forced Expiratory Volume (FEV), a key marker doctors use. You might cough more, feel chest tightness, or notice a dip in performance.

 

“If you are young, fit, and don’t have underlying conditions, you might still breeze through without noticeable symptoms, but don’t mistake that for safety. Your oxygen saturation might stay fine this time, but your body is quietly battling inflammation. And if you’re asthmatic, have COPD (chronic obstructive pulmonary disease), or a heart issue, you are playing with fire,” Dr Goyal said.

Can one marathon in smog cause long-term disease?

One workout won’t give you COPD or lung cancer. But in people already at risk, such an event can trigger asthma attacks, flare up COPD, or even precipitate cardiac trouble.

 

Amateurs often strain themselves harder and may not recognise warning signs like breathlessness or chest discomfort. Professionals may have stronger lungs, but fitness doesn’t protect anyone from inhaling more pollution.

 

Even elite athletes running a marathon in an AQI over 300 are harming themselves. The fitter your lungs, the more polluted air they’ll actually pull in.

 

Dr Goyal explains that even healthy lungs aren’t immune. Microscopic particles enter the bloodstream, lodge in tissues, spark inflammation, and can increase long-term cancer risk. “If you are not coughing today, it doesn’t mean your body isn’t under attack,” he says.

Should marathons be cancelled at certain pollution levels?

Here’s what experts suggest:

• AQI ≥ 200: Strongly consider postponing
• AQI ≥ 300: Cancel the event, no excuses

Event organisers have a responsibility to warn participants, publish AQI updates, and offer deferment options. There needs to be a clear cut-off where public health takes precedence over prestige.

Do masks, inhalers, or supplements make running safer in smog?

According to Dr Goyal, masks like N95 are not designed for heavy breathing during intense workouts. They lose efficiency and become difficult to wear. Bronchodilators are only useful for diagnosed lung patients. The rest, antioxidants, nebulisers, or supplements, offer no real-time protection against smog damage.

 

Dr Goyal says when celebrities or influencers post medal selfies while Delhi is choking, it sends the wrong message that smog is “just part of life.” It blurs the seriousness of what is a public health emergency and distracts from the real need for clean-air reforms.

 

“A medal or bike jersey is not worth the long-term harm to your lungs, heart, and overall health,” says Dr Goyal. 

Since you're already here

…and clearly interested in your health, take a moment to explore our varied range of stories on wellness, medical research, and public health insights.

• Caught flu despite the jab?  Why did I catch the flu even after taking the vaccine? Doctor explains
• Mental health help decoded  Psychiatrist vs psychologist: Who does what and whom to approach for help
• First therapy session fears?  Don’t fear therapy: Experts reveal what really happens in the first session
• Safe cough relief for kids  Do kids even need cough syrups? Doctors say they may do more harm than good
• Secrets of a long life  Want to live longer? Science says being active and organised is the key
• Heart under pressure  Financial stress and heart attacks: Why money matters as much as cholesterol
• Myths vs immunity  Vaccines, weather, kadha: What really helps immunity and what doesn’t
• Frown lines and fine lines  From frowns to smiles: These 7 tiny expressions speed up visible ageing
• Caring without crashing  Ageing parents, adult kids: How to grow together without burning out

For more health updates, follow #HealthWithBS 

This content is for informational purposes only and is not a substitute for professional medical advice.