expected samba during exhale walking

[tim.h]

I had about 10 minutes before I had to leave for uni so I decided to do a quick bit of apnea walking.
full exhale, because I didn't have much time.
40 steps (~25" per breath hold)
60", 45", 30", 4x15" breathing in between (no initial breath up)

They felt super uncomfortable, but full exhale always does. Tunnel vision on the 7th, I get that fairly early so I thought I would still make the 8th one. I did, but I fell over after one hook breath. I'm suprised because a)I thought that exhale breath holds increased the impact of rising CO2/dropping O2 and b)I used a pretty aggressive table that should have had CO2 skyrocket.

Where is the flaw in my logic? Is there such a thing as a CO2 table on full exhale?

 

[growingupninja]

You have it backwards. Exhale tables tend to lead to lower a build-up of CO2 and higher O2 deficit than full lung tables. You can easily be hypoxic without realizing it, and if you are decreasing your rest time, in the case of typical CO2 tables, then you could also not have enough time to reoxygenate during your recovery period, and since you are engaged in prolonged repeat apnea your venous blood and tissues which might otherwise have some O2 stores are also wrung out. So you get more and more hypoxic over the course of the table until you samba.

If you are getting tunnel vision doing dry work your body is obviously close to the edge.

 

[rovanpera]

So can you walk +10 minutes onfull inhale?

 

[tim.h]

Thanks for the reply, growingupninja.

What is it about the CO2 tables that makes them induce high CO2 rather than low O2?

 

[tim.h]

So can you walk +10 minutes onfull inhale?

Not yet..

 

[rovanpera]

A short recovery will reoxygenate you, but will not lower the co2 level much, so each hold should start with a higher co2 level than the previous hold.

 

[growingupninja]

There is probably literature on the subject but the body absorbs O2 much faster than it purges CO2; I would guess about 5 to 10 times faster. The other thing to realize between full lung and empty lung work is that on a full lung hold your blood O2 can hold constant for a while (it would depend on lung capacity, metabolic rate, etc but it can be well over a minute or two) before it starts to drop since all that air in the lung is acting as a buffer. On an empty lung hold it may start to drop in seconds.