As a daily jogger, I’ve come across plenty of tests to my mental fortitude. I’ve rolled my ankle, been chased by dogs and inhaled a fly after my presence startled it away from a fresh pile of dog poop. But I’ve never experienced the phenomenon of exercise heightening my sense of smell so much that someone making eggs a block away made me gag.
According to numerous posts on Reddit’s r/running, however, this happens a lot.
“When I run, I seem to become super sensitive to smells, especially food, to the point that if I run past a house cooking bacon, I feel like I’m going to throw up — and I love bacon,” writes one redditor. “I’ve googled around for this being a common issue, but haven’t found anything. So has anyone come across anything like this before? Also, I’m a 24-year-old dude, so I don’t think I’m pregnant?”
Multiple articles claim the “additional moisture in the nasal cavity” after exercise is what leads to a heightened sense of smell, but Paul Wise of the Monell Chemical Senses Center is skeptical. “Humidity may affect the sense of smell somewhat, as that’s been discussed as a possible contributor to airline food tasting bad,” he tells me. “I would tend to think this would be due to low-grade inflammation from dry nose, which could, in turn, affect how well air gets up to the smell receptors.”
That said, he’s not familiar with any official confirmation of this theory. “The idea that people have improved smell with exercise is a new one to me, frankly,” he confesses.
Wise does point to some research that ties one’s olfactory senses to exercise. Per a 2013 study in the Journal of the American Medical Association, people who regularly exercised were less likely to have lost their sense of smell in old age. But, Wise points out, this is probably a “larger health issue,” in that people who exercised regularly were simply healthier overall, and thus, less prone to mental decline in old age.
What, though, of runners in particular?
After all, the question is prevalent enough that it’s listed among the CDC’s Frequently Asked Questions page about environmental odors. “In general, developing odor symptoms depends on the amount of a substance (concentration) in the air that you are breathing, how often (frequency) you are breathing that air and how much time (duration) you spend breathing that air,” the CDC writes. “Jogging and other forms of exercise increase your breathing rate, making you breathe in more of the odor. During bad odor days, exercising indoors or in another location can help.”
In short, in the same way many runners find more snot falling from their nostrils while running thanks to breathing in more air at an increased rate, they’re probably getting a giant load of whatever smell is attached to those air particles as well.
As for why some runners might get sick from these smells, the CDC says environmental odors can cause a number of symptoms — from headaches, to heart palpitations, to nausea. Whether or not you’ll suffer from them mostly depends on how sensitive you are, and the concentration of the smell. “These symptoms generally occur at the time of exposure,” the CDC explains. “Their intensity will depend on the concentration of the odor in air, how often you smell it and how long exposure lasts.”
Thus, if you’re a jogging super-smeller, you’re probably better off sticking to trails and parks, rather than streets and alleys. And if you’re a city dweller like myself and not afforded such luxuries of nature, a little Vicks VapoRub under your nose can apparently go a long way, too.
And with that, I’ll smell ya later.