When you yawn, do you breathe in or out?

Initially I breathe inward, then a giant exhalation. (is that a word?)

Mcbealer. That is not weird. Pretty much all yawns reflect a giant inhalation (breath inward) followed by a slow exhalation. There isn’t much variation to this.

I’m the same as you McB.

@ TheHaight ~ a new variation on my name ~ I like it :0)
@ Shilolo~ oh good, exhalation is a word. thanks!

haha, it is a pretty catchy nickname. ;)

@Shilolo: Is the purpose of a yawn to increase intake of oxygen? Or just some body language when you are with boring people?

@Gail. The exact physiologic basis of the yawn reflex is not known. In particular, why you yawn during boring English lessons is a hot area of research right now. But I digress. You are right that in some cases the yawn is to increase oxygen intake, but how that correlates with tiredness is unknown.

@shilolo
Oxygen is used in respiration to increase ATP, therefore you would have more energy, and probably be able to stay awake much easier. also your breathing slows as you get tired, meaning you would need more oxygen…
I would have thought the reason why when you yawn, then everyone around you yawns is because it’ll be one of those things like it was beneficial for the whole group of humans in a pack to do it, like to get a bit more oxygen. Bit hard to explain, but I mean like when you see someone else being sick, you want to be sick because originally it meant that they had eaten something bad, and you might have eaten something bad too, so it was a natural reflex to be sick.
Having said all that, it doesn’t answer the question
so, to answer the question, I’m with everyone else saying that I take one long breathe in, and then exhale very slowly.

@cage. You are confusing cellular respiration (the use of oxygen for the generation of ATP) and physiologic respiration (respiration, or breathing). It turns out the oxygen is not the main regulator or human ventilation, but rather, carbon dioxide. In fact, it isn’t even carbon dioxide that regulates breathing, but the change in pH of the fluid in the brain, which itself is dependent on the carbon dioxide in the blood (or more precisely, the bicarbonate ion).

Physiologic control of respiration is extraordinarily complex, and still incompletely understood. Your statement about slow breathing when you sleep is true, but that you would need more oxygen is false. Even though your respiratory rate slows down, your tidal volume (the amount of air you “move” with each breath) increases to maintain minute ventilation (meaning, how much air do you “move in one minute”, which is the product of the respiratory rate and tidal volume).

I can’t remember where I read it but I think yawning is a signal to predators. “Look, you might have noticed that I’m sleepy, but I’ll bare my teeth to you to show aggression.” Then the other animals with you say, “yeah, me too” (yawn)

Edit: I read it from brownlemur here. He knows everything.

Brownlemur rules.

Anyone ever snort during a yawn? If “snort” is the correct word. Kind of a backward “hoch” that usually signals yawnus interruptus.

@knot; no but I’ve swallowed a hiccup before :)

inhale deeply and then an even greater exhalation