First Freedom, as a fellow bow hunter I must admit I look for every incremental change that can give me an edge. I will wait until a deer that is walking broadsided to me takes a forward step with the onside leg in order to expose more lung tissue and the heart better.
Well, I have *heard* that the lungs expand much much larger - like 2 to 3 times the size on the "uptake" - I'd much rather HIT lungs full of oxygen than MISS lungs without.
While this might be true I highly doubt it. I am actually fairly knowledgeable about human lung physiology.
The typical human lung for about a 70 kg male will have a total lung volume (TLC) of about 6 litters. Someone who exercises will typically have a little greater lung volume. I would expect a 70 kg deer to have a large lung volume.
OTH that same 70 kg male will have a resting tidal volume (TV) of about 500 ml (1/2) a litter. This can vary a little with some, but for the most part the changes are rather small. I would expect a deers to be somewhat similar. Cold however will increase the basal metabolism and cause an subsequent increase in the resting tidal volume.
For the purposes of the calculations I will choose a TLC of 6 litters (however I feel like this is quite conservative, again I feel deer are designed to run and are more fit therefore they will have a much larger TLC) and a tidal volume of a litter. The change in total volume from inhalation to exhalation would then be about 16.7%. This is of course at rest.
It the deer is running however there will be a much larger change.
Also keep in mind that deer like men have two lungs so the change on each side will be evenly divided to about 8.5% I doubt this would translate to any significantly larger target area.
Honestly even if the change were worth it I simply am not good enough to time it out with a bow.
I hope this helps.