If you don't want to hyperventilate I have found I tolerate empty lung statics better in a seated (e.g. 'half lotus') position, where they can also be combined with pressure adaptation /compensation manoeuvre exercises:
- apnea after full exhale + held diaphragmatic introflexion ('uddiyana bandha' in sanskrit)
- apnea after full exhale + 10-20 reverse packs
These both train diaphragmatic flexibility and ribcage elasticity and will therefore make hydrostatic pressures more tolerable. The latter also trains the 'mouthfill' manoeuvre, vital for compensation in FRC or extreme inhale diving.
I would suggest 3 of each in that sequence, with 2 - 3 minute recoveries. I don't know about going to LMC, not because of danger (there isn't any in DRY statics) but because I have a hunch that the body 'learns' to LMC, and there is a greater tendency to do so thereafter.
As a sidenote yogis insist that apneas are performed in a seated position, so as to enable access to the 3 locks (bandhas) and channeling of kundalini energy from the coccyx. They also advocate bhastrika (an agressive form of hyperventilation) before long pranayama holds. Also if you want to master the 'breathless state' you need to cut the frenulum on your tongue so that you can force it back down your throat to stop contractions...
Carlo, haematocrit will increase blood viscosity, but if the rise in hct is natural (autostimulated) then the organism has countermeasures to balance viscosity. For example I have experienced a huge drop in platelets, which are responsible for blood clotting and thus thicken the blood. Viscosity agents are also released, but you will have to wait for Seb to explain those.
