Why does running up stairs clean my sinuses?

October 10, 2004 8:35 PM

When I have a stuffy nose from allergies or a cold, jogging up a flight of stairs momentarily reduces the swelling of the nasal passage. Ascending at a walk does not have this effect. Why? Is it the change in air pressure? The bounciness of my gait?
posted by Scoo to health (7 comments total)

The pressure differential sounds unlikely, as this would equalise through your mouth, and is negligable compared to the pressure of closing your mouth and blowing/sucking. The 'bouncy gait' sounds more likely, I've definately had jumping up and down clear up a nasal congestion temporarily (and entertain my environment).
posted by fvw at 9:01 PM on October 10, 2004

For the same reason that Afrin works on your stuffy nose.

Most of the stuffiness of congestion is due to dilated blood vessels in your nose (part of your body's inflammatory response to the virus or allergen). When you run up stairs, you pull blood out of those vessels and down toward your legs. Afrin acts as a vasoconstrictor, causes the vessels to decrease their diameter, therefore allowing less blood into them, and less congestion.
posted by gramcracker at 9:12 PM on October 10, 2004

I would suspect that the dilated vessels in your nose are sensitive to task-related demands from the brain. When you start exerting, there are a whole host of autonomic nervous system responses that optimize your body for the job. One way might be to draw blood away from the GI tract and spend less effort on digestion for a little while---this is a classic "fight or flight" response. Another way is to make respiration easier. gramcracker, you're the medical student and not me, but is it likely that the slight amount of blood in the sinuses really enhance running capacity when diverted toward the legs? (A sincere question--not meant to be snarky.)

If I were a neurophysiologist, I would probably start blathering on about histaminergic projections from the blah blah influenced by projections from the hoo ha and so forth. See also the Wikipedia entry under antihistamine.
posted by tss at 9:43 PM on October 10, 2004

...which tells us that histaminergic cells in the brain probably don't have much to do with allergic reactions in the nose per se. So much for trying to sound intelligent. Nevertheless, I stand behind my hunch of a CNS response that makes respiration easier, without any specific claims to neurotransmitters involved.
posted by tss at 9:50 PM on October 10, 2004

tss--you're right, the fight-or-flight response will tend to constrict blood vessels (to maintain blood pressure). When true sympathetic (fight or flight) kicks in, I believe your body will divert as much blood as it possibly can to muscles needed to do the work (even the nasal vessels).

And good point about easing respiration.

I've had the "running up the stairs" effect before, and for me it only lasts a matter of seconds--5 or 10--and then I'm back to stuffiness, even if I continue running on flat ground, so I'd guess it's only a blood pooling thing, but I could easily be wrong.

As for allergies--you'd want to check out mast cells. They're the buggers responsible for allergies. (Interesting fact: they're important for fighting parasites in our bodies, so when you have an allergy, it's mast cells that are dumping histamine granules into your body that cause runny noses and watery eyes. These reactions not only cause hay fever, but are thought to help the body clear parasites. So that's why antihistamines work--they stop histamine reactions.)
posted by gramcracker at 9:58 PM on October 10, 2004

To add onto gramcracker, the going theory is that our allergies stem from back in Africa (think "out-of-Africa" theory) where parasites, partically worms, infiltrated much of the human population. Allergies and the cells associated with them supposed evolved to fight off these parasitic worms. Move thousands of years into the future in civillized areas, and these cells no longer have any useful function. However, they still kinda of want/need to do something, so they create their own enemies, aka allergins. My biology teacher also told us people where parasites are abound do not have allergies like us because those allergy-causing cells have their primary function in the body again.
posted by jmd82 at 12:12 AM on October 11, 2004

jmd82, I have some reservations about your (biology teacher's?) out-of-Africa mast cell theory. Non-human animals (dogs and cats came up on the google search, but I'm going to wager that most mammals) also have mast cells. I don't think humans specially evolved mast cells; they were probably part of the mammalian genome long before the first hominids.

I am not an expert in evolutionary biology, but there's something that feels very racist about the "out of Africa" meme, as though some of the biological and behavorial adaptations humans have today are due to the "savage" conditions of Africa, about 100,000 years ago--rather than from 4.6 billion years of evolution.
posted by LimePi at 1:26 PM on October 11, 2004