Inhale through nose, exhale through mouth?

[Dids]

I was watching some health-type programme covering how to worry yourself silly that every minor ache or sore could be a precursor to assorted fatal diseases. It was the usual Japanese format of some filmed piece, then a panel of Z-list celebrities would make comments on it.

However, one bit struck me as odd: one of the panel suddenly came out with how it was important to always breath in through the nose, out through the mouth. The rest of the panel nodded along, and even my wife added something about how I should remember that too.

I've done a search of the web, and all I found was tips on ciggie smoking or yoga breathing exercises, where I guess that the focus on breathing is as part of a relaxation/meditiation technique rather than the change in the type of air you get. Is there any sound medical reason why breathing through one or the other orifice may be "good". I suspect nose hairs or whatever might filter out some pollutants, but surely not enough to make any significant difference?

 

[El Greco]

I don't think that any large scale studies can be found about this (how can you see whether subjects comply ?) but this advice always seemed stupid to me. When you are resting and have no nose congestion, the natural thing to do is inhale and exhale through nose. When exercising, you will necessarily breath in and out mainly through mouth. If I try to inhale through nose and exhale through mouth while at rest, I look like a goldfish.

Even if we accept that inhaling through nose filters bacteria, why should we exhale through mouth ?

 

[ceptimus]

I was told that ridiculous story as a child. I even tried doing it for a while.

If God, or evolution, decided this was a good scheme, we would have non-return valves in our nasal passages.

 

[bjornart]

So you don't wear out your nose with unecessary filtering out outbound air of course.
I think there's no good medical reason to inhale through your nose and exhale through your mouth, it's just a result of garbled logic. "Yoga is good for you, yoga involves breathing exercises where you breathe in through your nose and out through your mouth, yoga incorporates this because it's good, and you should do it all the time."
If it's cold you'll heat the air slightly more if you breath in through your nose, but you'll also freeze your nose off.

 

[BillHoyt]

Even if we accept that inhaling through nose filters bacteria, why should we exhale through mouth ?

It dates back to ancient Jewish dietary laws. To keep a Kosher house, you need to separate milch from fleisch. To keep a Kosher bod, you separate mucous from food stuck between your teeth.