Question CO2 tolerance and its relation to swim performance

[Matthew J]

Greetings, everyone

This is my first post. I've had a question rolling around in my head for a while and thought that, perhaps, the right place to go would be where people live and breathe (pun intended) CO2 tolerance training. I've asked this question to swimmers and they mainly end up with no ideas or much thought. I've been a competitive swimmer for a good portion of my life, then triathlete, then cyclist, then swimmer once again. I'm currently training to attempt the national record in the 200 FR in my age group. That's my quick background.

CO2 tolerance seems to be one fundamental metric of fitness. The higher one's tolerance, the more depressed the breathing response for any given level of CO2. As a swimmer that's a good thing. The swimming world still calls restricted breathing sets 'hypoxic sets'. I believe (correct me if I'm wrong), that's a misnomer since it was shown that there's little oxygen stress restricting breathing to every 3rd or 4th stroke; it's mostly a CO2 stress.

Right now, from the moment I get in the water to the moment I get out, I breathe every 3rd stroke during freestyle training. It took me about 5 weeks to acclimate to restricting my respirations to every 3rd from every 2nd. (Key point: When it's race time, I switch to breathing every 2nd to take advantage of the higher CO2 tolerance).

I'm wondering how far I could take training my restricted breathing and have it be beneficial. Would there be an advantage to acclimating to breathing every 4th by default? Or 5th? How far out could the body acclimate? Would there be a point of not fully acclimating and a de-training effect take place? How far to push this and have it be advantageous? There seems to have been a large benefit to acclimating to breathing every 3rd from every 2nd.

Any thoughts you free-divers have would be awesome. Thanks for your time.

 

[J Campbell]

When you say every 3rd you mean: right (arm), left, right/breath, left, right, left/breath, right, left, right/breath ... so your breathing alternates left to right as you go through the cycle - correct? That's the way I swim laps too. I'm not sure how long of a sprint I could do with every 3rd breath. But I also do laps of every 5 strokes up to 100 meters, not sprinting - then I get a severe CO2 buildup and stop. But I think a highly trained swimmer would probably be able to do 200 sprint on every 3rd breath. Just speculating here with no direct experience in this.

 

[J Campbell]

Also, when I started doing this left/right breathing it was disorienting - kind of dizzying. But it's not a problem any more.

 

[Matthew J]

J Campbell: You are correct. Generally it's called bilateral breathing. It's beneficial for a few reasons, one being it makes for a more balanced swimmer, being comfortable breathing on either side, even though one may have a preferred side.

A 50 sprint is generally swum with no breathing (if the swimmer can handle it). A difficult feat. At the rate of speed a swimmer has in a 50, the surface friction is so high that any rotation to breathe is slowing the swimmer down. Training for an all out 50 with no breath is very hard. A very high CO2 tolerance is a must. In competition, anything 200 yards/meters and over is done breathing every 2nd, usually on the swimmer's favored side. The 100 is controversial. If you want to start an argument among coaches, ask them what the breathing pattern for a 100 FR should be. A swimmer is always more streamlined during no breathing. There's always a little brake during the rotation to breathe.

 

[cdavis]

If breathing less causes less drag, the less the better. You can probably get to every 4th stroke in practice and every 3rd stroke in competition, with sufficient training. More than that and other things will begin to interfere. Your 02 saturation will eventually begin to drop. Training will get you used to operating at lower 02 sat, but there are probably other things we don't know about. Co2 cnc also will rise the longer the swim. Hence the coach'sarguments about 100 vs 200. It is going to be pretty individual and experimental, what works for you. And over training in this type of thing is a real possibility. One possibility is going from 3 strokes for the first 100 to two strokes for the second.