Breathing physiology... whats best for off-gassing

[pescador775]

Netdoc is correct, of course. Dr Thomas provided his usual brilliant insight. The only effect that vertical posture will have on breathing is related to the respiratory diaphragm which will be pushed up slightly by the pressure differential. There will be a slight increase in overall effort due to the regulator demand valve being higher than the lungs. There will be no change in outgassing. There will be no 'dry suit effect' which is oversimplistic. The whole issue sounds like the output of somebody who is driven to self promote, publish or promote a 'philosophy' or course of instruction.

 

[The Chairman]

Netdoc is correct, of course.

engraved on my tombstone AFTER I die of old age on a undisclosed Caribbean island. :tease:

Of course, if I could ever get old Roak to admit it, I would probably die of shock in my prime!!! :tease: :tease:

But thanks for the support, Pescador! I knew I wasn't the only one to see the reasoning.

 

[Dr Deco]

Dear Readers:

Lungs and Gas Exchange

The truth be told, normal lungs are not the limiting factor in gas exchange- even if bubbles are present. If someone has emphysema, then we are talking about something else. Here an individual would have a high degree of ventilation (= air in and out) in essentially useless air sacks (= alveoli) because they are too large and not supplied well with blood capillaries. This is not your normal diver. Divers are healthy individuals.

The blood supply to the lungs is seldom a limiting factor (if ever) in a healthy individual. When we are running and huffing and puffing, our ability to sustain the fast pace is not because we are not getting enough oxygen or eliminating enough carbon dioxide through the lungs. The limitation is within the muscles themselves. This is “cured” through training and is also influenced by genetics. Some folks are walkers, some distance runners, and some are sprinters. :crawl:

Perfusion

Blood flow in the legs is influenced by body position on dry land. There is a hydrostatic (= pressure) gradient when you are in air (and gravity) and blood “pools” in the legs. If you are reclining, this gradient is gone. When you are in water, the gradient does not exist. Perfusion is not a function of body position in the water.:mean:

Exercise

The key to better gas exchange is exercise in the arms and legs. This is not theoretical. The gas-exchanged properties of exercise are documented and quantified. We use them all the time at NASA to prepare astronauts for space walks (=EVA).

Dr Deco :doctor: