exercise -diffusion limited?

[aspiringmd1015]

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is this true because the increased cardiac output during exercise increases your cardiac output to the point where it can't match the incoming 02, so the two don't equilibrate, and thus a diffusion limited situation?

 

[Lafakads]

I think that would only apply to people with some kind of lung or heart problem.

A normal individual during exercise should equilibriate and be perfusion limited.

 

[scoKraz4]

If you are talking about more blood flow through the lungs, that is a perfusion limited situation for O2. The concentration gradient is still large enough for O2 to fully saturate the blood so that PaO2=PAO2. If you have pulm fibrosis though the barrier between alveoli and capillary is thickened and thus O2 poorly diffuses down it's concentration gradient into the blood. So then you have a diffusion problem.