I'm not sure if this is the right site to ask this, but it seemed like the best option.

I've observed on myself that, if I stand on a train platform and a cargo train drives by, creating strong, short gusts of wind, it becomes harder to breathe for me during the gusts, almost like fighting my body into breathing.

A commenton parenting.se leads me to believe this is due to the mammalian diving reflex.

1) is this assumption correct? 2) what causes the change in breathing?


So I'm going to go ahead and tell you outright that it is not the diving reflex.

What you are experiencing is the effect of air pressure.

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Our lungs work off of pressure. Specifically our lungs inflate by using "negative pressure" (a word I've always hated). The pressure is not actually negative it is simply lower than the surroundings. Since there is less air in your lungs the air from the atmosphere rushes in because the pressure is higher outside your lungs. This is Boyle's Law (not the pressure outside being higher, but what happens when your lungs expand). Where an increase in Volume means a decrease in Pressure (if all else remains unchanged). In fact plants pull water up using negative pressure.

However to push out the air from our lungs we supply pressure using our muscles that overcomes the outside pressure and forces the air out.

The reason you feel your breathing change is because when that train passes by you correctly observed the strong gust of wind. This gust of wind has some force behind it that normally is not in the air you are breathing from the atmosphere. It has more force which increases the air's velocity. This actually decreases the pressure, but there's no need to get into that here (Bernoulli's).

The reason it feels like your body is "fighting to breath" is because the air is traveling in a direction with some force that you need to overcome by opening up your lungs just enough to "suck" the air in with negative pressure. This is more than the pressure you usually need to produce in order to breath in air that is "still".

What is funny to think about is we don't really have a muscle that "pulls" air in, even though it feels like you are actively doing that. The air actually rushes in on its own. All you do is expand your rib cage, which your lungs are attached to (look up on how, it's actually pretty cool), thereby making inhalation occur.

Now an interesting question for you to ask yourself is why is cold air harder to breathe?

  • $\begingroup$ Excuse my comment, but I don't see how your theory holds up, considering your lungs are in equilibrium with the outside pressure. Even in complete vacuum you would be able to perform a thorax motion, that could be perceived as breathing in. The perceived struggle to attempt the motion per se seems hard to be justified this way. Also regarding your comment about trees (especially if above 10m) please consider reading these answers: biology.stackexchange.com/questions/11044/…. $\endgroup$ – KaPy3141 Mar 16 at 22:29
  • $\begingroup$ Also, the diving reflex is known to be triggered by ambient temperature, or better to say, the increased heat-capacity or heat transfer of water compared to air. The sheering forces created by passing air significantly increases the effective heat-transfer, which might be perceived as being submerged in water. $\endgroup$ – KaPy3141 Mar 16 at 22:31

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