Question about breath holding?

[vilistaja]

Why is it so that if i do static apnea tables then four first repeats are harder than last four although recovery time gets shorter?

Also i am doing walking apnea training in sets:
30 sec hold, 60 sec recover 4x
40 sec hold, 60 sec recover 4x
50 sec hold, 60 sec recover 4x

and i don't understand why there is my first two holds harder than if i for example do my second 50 sec attempt?

 

[Rik]

I am not sure if there is an precise bio-chemical explanation. Especially not without looking it up, however, it is an known phenomenon where later (comparable) breath-holds are easier then earlier breath-hold.

It might probably some warming-up phenomena, with better breath-holds, better technique and better mental preparation compared with the first breath-hold.

 

[growingupninja]

Why is it so that if i do static apnea tables then four first repeats are harder than last four although recovery time gets shorter?

Also i am doing walking apnea training in sets:
30 sec hold, 60 sec recover 4x
40 sec hold, 60 sec recover 4x
50 sec hold, 60 sec recover 4x

and i don't understand why there is my first two holds harder than if i for example do my second 50 sec attempt?

Your body is becoming accustomed to the higher than normal CO2 levels by that 3rd hold. Your dive response is also stronger on the initial holds, so if you were holding for a longer, constant time you would end the hold with a higher blood oxygen saturation on hold #1 vs say hold #6. With a 30 second, full lung holds though it is almost CO2 that is triggering your urge to breathe.

If you are diving all day, etc--spearfishing for example, it is important to realize this. When you start the day, your body is going to be telling you to breathe much, much sooner than after several hours of diving.