Why is my 3rd go so much easier than 1st?

[levee]

Hi everyone!

I'm new to this forum and this is my first post. I'd like to know what your experience is. OK, here goes the thing: whenever I do static (dry or wet), they get gradually easier/longer. Example...

1st static - 1'52
2nd static - 2'52
3rd static - 3'35

The thing is, my first static is NOT a warm-up! It's the best I can do at that moment. The urge to breathe just gets too strong. The 3rd static is much easier, meaning for 2 minutes I don't even feel I'm breath-holding. Why is this happening? What is your experience?? I'm adding some more info to explain how I practise.
I never hyperventilate. I do just a short breath-up. Pauses between attempts are about 2-3 mins. I don't worry about times too much, I just keep holding until the sensation becomes unbearable, I always try to listen to what my body is saying to me. Contractions come quite quickly, usually between 0'30 - 1'00 but they are not a problem. When they appear I just think: Hi contractions, good to see you again, how have you been? I've read Pete Scott's (Laminar, I believe) post on First go/adaptation system, very interesting, I really liked that!
And my modest PB's so that you know who you are dealing with
STA - 5'11
CWF - 32
FI - 31
DWF - 75 (oops, I don't know why but I just don't enjoy diving with fins very much...it feels ...eeeee....unnatural.... just my opinion, no offence!)
DNF - 100 (I DNF and FI, It feels so good!)

Well, that's it. Looking forward to your comments. Take care and enjoy life!!!

[fcallagy]

Hi levee, I would say they get easier due to the body going in to dive mode, dive reflex etc

[levee]

Hi fcallagy,

thx for reply. Yep, that makes sense. What is your experience with static vs dynamic? My DNF first-go is usually the best, then it gets worse. And it's the other way around with STA. Body getting tired faster during dynamic, perhaps?