Many runners are performing ‘snot rockets’ in public spaces, turning parks and pavements into an impromptu mucus minefield this spring. The technique – blocking one nostril with a finger and exhaling sharply to expel a projectile clump of nasal mucus – has become so common that entire online forums are dedicated to debating it. On Reddit’s r/Running subreddit, one user admitted to shooting snot rockets while running, describing himself as “like a faucet that does not turn off until I’m finished running”. Another joked that once the temperature drops, their “nose runs faster” than their legs, while a third simply declared running “gross”. The practice is not confined to runners: Premier League footballers are frequently spotted doing it on the pitch, and some swimmers have recalled seeing fellow pool-goers release mucus into the water.
The science behind the snot
The urge to fire a snot rocket is rooted in a physiological response to intense exercise. A 2017 study published in the International Journal of Otolaryngology found that between 27% and 74% of athletes experience rhinitis – a medical term for a runny nose. The wide range reflects different environments: aquatic athletes and those training in cold conditions show an increased prevalence, likely due to irritants affecting the nasal lining. While track and field athletes do not show a significantly higher rate than the general population, other studies suggest regular exercise is associated with an increase in rhinitis.
Dr Adam Staten explains that a bit of snot is a normal bodily response during exercise. When you run, your breathing speeds up because of increased demand for oxygen, pulling much more air through the nose and airways. The nose warms and filters this air before it reaches the lungs, and mucus production is part of that process. The increased airflow, especially in cold or dry conditions, can dry out the nasal lining, triggering the nose to produce extra mucus to compensate. Exercise also activates the sympathetic nervous system, which constricts blood vessels in the nasal passages – this normally opens the airway, but the faster airflow can lead to even more drying, spurring further mucus production. For individuals with allergies, inhaling more air during exercise means increased exposure to pollen, dust and mould, exacerbating symptoms. Non-allergic triggers such as cold air, strong smells, pollution and exercise itself can also provoke a runny nose.
When it comes to gender, there is no scientific difference in how much mucus men and women produce. Dr Mohammed Ditta reports that allergic rhinitis is more common in boys during childhood but switches to women in adulthood. Non-allergic rhinitis, triggered by cold air, strong smells, pollution or exercise, is frequently reported by women, although anyone can get it. “If men seem more likely to do visible ‘snot rockets’,” Dr Ditta adds, “that is more plausibly down to behaviour, social norms, and exposure patterns rather than a biological factory making extra mucus.”
Etiquette, disgust and the social divide
For every runner who sees the snot rocket as a necessary evil, there is a fellow park-goer or runner who finds it deeply offensive. Emma, 26, told Metro that she often runs with her boyfriend and that his snot rocketing makes her “want to hurl”. “We’ll be on the side of the pavement and out of nowhere, he’ll take his fingers, block one nostril and exhale sharply, releasing a projectile clump of snot,” she said. She acknowledged he never does it when anyone is walking by, but she still hates it: “All I can think as it lands on the road or pavement is that some poor unsuspecting pedestrian will step in it and track it home where it will become encrusted into their nice carpet.” She tells him off “time and time again” but nothing changes. “For the life of me, I can’t understand why he can’t wait 10 minutes to blow his nose when we arrive home.”
Etiquette experts are unequivocal. Laura Windsor told Metro: “You should never do it in places where there are other people, first of all because it’s disgusting, and secondly because you’re making people feel uncomfortable. Etiquette is about making people around you feel comfortable. In a public space context, no, definitely not. No one wants to see you excreting mucus from your body.”
Jo Hayes, founder of EtiquetteExpert.org, suggests runners who regularly experience snot build-ups should simply carry a handkerchief. “Or, at the very least, remove yourself far from the sight/sound of any other human and deliver your snot rocket into a bush. Ensure it hasn’t landed on a walking path, or anywhere other humans will be,” she said. “Further, ensure there is no residual snot on your face or body. We’re humans, not animals. We have (most healthy people) control over our bodily excrements, and can hold their release for appropriate situations. I’ll end with a reminder of the Golden Rule for life: do unto others as you would have them do unto you.”
The debate spills into other sports. Some pool-goers have recalled seeing swimmers release mucus into the water. On Reddit, one user admitted: “I blow my nose and spit in the pool and push it into the gutter. Also spit out any phlegm whilst I’m swimming if I need to.” This behaviour mirrors the runner’s justification: a perceived need to clear airways during exertion, regardless of the setting. Yet the social contract of shared public spaces – be it a park path, a football pitch or a swimming pool – argues for discretion.
Practical alternatives for runners
For those who struggle with a runny nose on every run, experts point to several coping mechanisms that avoid forcing others to dodge bodily fluids. Saline nasal sprays can help moisturise nasal passages and clear irritants, potentially reducing the need for a forceful expulsion. Staying well-hydrated supports mucosal moisture. Focusing on nasal breathing during exercise may help humidify the air before it reaches the lungs. And, of course, carrying a handkerchief or tissues is the simplest way to avoid the snot rocket altogether – a recommendation that etiquette experts insist is non-negotiable in public. On Reddit, one runner confessed he would “love to find a way to spit less while running, as it’s a bit gross when running with new friends that aren’t used to it”, yet he still does it. Another noted that anyone who has run a marathon has likely “pooped behind a dumpster, or in the woods”, adding: “They send that snot rocket, they wipe it on their clothes if need be. So if you want to run, you gotta be comfortable being gross.” The tension between that runner’s culture and the expectations of polite society shows no sign of easing – and the next time you pop out for a walk in the park, you might want to keep an eye on the pavement, for fear of treading in something stickier than you bargained for.