On 8/27/2012 4:38 AM, Merle Lester wrote:
/Military: /Can you imagine a navy seals capability when they wouldn’t
need to surface for air and could stay underwater for over 20 minutes?
There's a catch:
In addition to absorbing O2 the lugs exhale CO2. Our metabolic engines
have exhaust. The CO2 buildup in the blood is what causes the intense
urge to breath when you hold your breath - not the lack of O2. That just
makes you quietly pass out.
Free divers do not hyperventilate before diving to increase O2 levels,
as the blood is already 100% saturated when breathing normally. The
hyperventilation purges more CO2 and allow more time before the need to
breathe becomes hard to fight/CO2 becomes dangerous.
This CO2 buildup progresses to disorientation, panic, hyperventilation,
convulsions, unconsciousness, and eventually death.
https://en.wikipedia.org/wiki/Hypercapnia
20 minutes? How many could fight this that long if active/conscious, and
how long before blood CO2 levels become toxic or fatal?
Many saved from drowning note the struggling stops in about a minute and
a calm/euphoria sets in - but that means you're about to fade - and
have only a couple minutes before permanent neurological damage begins
(very cold water slows this down). With supplemental blood O2, you'd
keep struggling/panicking a lot longer. Dealing with this would take a
very strong mind and a lot of practice. Few could manage it, until the
CO2 injures or kills them.
KG
