Freethought & Rationalism Archive

Nowhere357 · 05-09-2003, 12:31 PM

Quote:

Originally posted by ps418
Oh, we did something like this when I was a kid. You'd hyperventilate until you felt really light-headed, then you'd take in a deep breath and hold it, and then a friend would give you a big bear-hug from behind.

Wow, this brought back memories I forgot I had! What a rush, both the recall and the experience.

Is it a fact that hyperventilation destroys brain cells? I assume it does, but I also think neurons regenerate, especially in kids. I'm not sure, though.

Wyz_sub10 · 05-09-2003, 02:13 PM

Quote:

Originally posted by The Lone Ranger
On the other hand, I've read claims that by "hyperventilating", some people can lower the CO2 levels in their blood enough that if they then begin to hold their breath, they'll pass out from low oxygen before CO2 levels build sufficiently to trigger the involuntary breathing response. Supposedly, it's dangerous to hyperventilate before trying to swim any distance underwater for that reason, because you may pass out while under the water.
Cheers,
Michael

Hmmmm...I recall from second-year physiology that you can actually hold your breath longer after a period of hyperventilating.

Do you not increase the oxygen level in your blood through hyperventilation, thereby allowing you to go longer without oxygen?

Or, like the other 3 years of biology, this is something my memory has mangled?

The Lone Ranger · 05-09-2003, 03:40 PM

Quote:

Originally posted by Wyz_sub10:

Hmmmm...I recall from second-year physiology that you can actually hold your breath longer after a period of hyperventilating.

Do you not increase the oxygen level in your blood through hyperventilation, thereby allowing you to go longer without oxygen?

Or, like the other 3 years of biology, this is something my memory has mangled?

Nah, hyperventilation doesn't really do much to increase the oxygen levels in your blood; what it does is lower the CO2 levels. This does increase the amount of time you can hold your breath, though, since it will then take longer for CO2 levels to build to the point that your involuntary breathing response kicks in.

There's more oxygen in the air than your lungs can remove, which is why mouth-to-mouth respiration works. The hemoglobin in your red blood cells is pretty-much saturated during normal breathing.

The reason your respiration rate increases with exercise is not so much to get more oxygen in as to get excess CO2 out.

Or so I've read.

To clarify:
In the physiology labs I've taught, we sometimes do an experiment with rabbits to show how low oxygen and high CO2 levels influence respiration.

When we have the rabbits breathe very-low-oxygen air without added CO2, their respiration becomes very deep, but not faster. Presumably, this helps them to more efficiently flush "stale" air out of their lungs and get in the maximum amount of O2.

When we have the rabbits breathe high-CO2 air (even if the oxygen content is normal or even enriched), the respiration becomes much faster. Presumably, this is to help them excrete excess CO2. The same result occurs if you acidify the blood with carbonic acid (which the lungs excrete as CO2).

Cheers,

Michael

Secular Pinoy · 05-09-2003, 07:01 PM

Well, you could always try swimming with cement shoes.

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05-09-2003, 07:01 PM	#24
Secular Pinoy Veteran Member Join Date: Feb 2001 Location: Quezon City, Philippines Posts: 1,994	Well, you could always try swimming with cement shoes.

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