VO2Max is to do with the body's maximum capability to use oxygen during intense exercise - i.e. higher VO2Max typically means you can exercise harder/faster (for longer), whereas that's clearly not quite what's needed for long breathhold (certainly not static, at least, but even dynamic is meant to be pretty relaxed!)
Consequently, it's possible it may not be quite so important for BH as you might expect. -Though that also doesn't necessarily mean that the adaptations that lead to increased VO2Max wouldn't also be useful for BH...
So.. here's some research looking at BH performance related to a number of physical attributes, including VO2Max:
Breath-hold diving performance factors, FERNÁNDEZ et al, Journal of Human Sport and Exercise, vol.12, no.3, 2017
https://www.redalyc.org/pdf/3010/301053359003.pdf
This suggests little correlation between VO2Max and BH performance (slightly negative, if anything).
The highest correlations were with height and lung volume (vital capacity), as well as min heart-rate during BH (i.e. lower is better).
We've already been considering height & lungs in previous posts (sadly for those of us more challenged in those areas), and I guess it's not such a surprise that having lower heart-rate could be helpful.
There's also that strong correlation with reduced spO2 at end of BH (esp. static). It doesn't seem so surprising that longer BH would tend to lead to lower O2 (likely at end of BH) - but I do think it leads to a couple of interesting extra questions here...
- Obvious first question: does height correlate with VC? (would assume likely true)
- Second more interesting question: does higher spO2 correlate with higher VC (and height) for similar BH times?
I.e. for a similar BH time, do those with smaller lung capacity end up with less O2 compared to those with greater VC? Or does spO2 end up pretty similar for similar BH times no matter the size of lungs or height?
If the latter, it might suggest that O2 use is also increased for those with larger lungs(/height), but would also suggest the possibility of a somewhat surprising correlation between lung size (/height) and ability to withstand hypoxia (since it'd mean those with larger lungs (/height) tend to have longer BH despite their increased O2 use - so their lower spO2 suggests the advantage comes from hypoxia tolerance rather than VC/height!)
Conversely, the former would suggest that the BH advantage really does simply come from larger lungs (/height) - but then it begs the question of why spO2 has an equally strong correlation with BH performance? (Since the larger lungs /height should mean that's where the advantage comes from, and spO2 wouldn't come into it so much.)
Probably the answer is simply that VC/height and hypoxia tolerance are fairly independent, but end up contributing to BH capability to a roughly similar degree. (The data could potentially even show that those with smaller lungs end up with better hypoxia tolerance 'cos they're having to do more to 'keep up' with those who have larger lungs...?)
Another correlation, slightly less strong than the above, was with "body lean percentage".
TBH, I'm not sure I understand what this means... It seems to me it should be the opposite of "body fat percentage" (i.e. the two add up to 100%), yet there is no clear correlation between BFP and performance, despite the fairly strong correlation between BLP and perfornance, so that's clearly not the case...
Maybe someone could enlighten us about this...?
HOWEVER... having said all of above, there are a couple of obvious caveats to this...
- Those taking part in this are competitive freedivers, so the results may not apply immediately to the rest of us mere mortals.
- All of them were male - so, sadly, we have no comparative data for female competitors.
Here's another research article looking at synchronised swimmers instead (in the end, though, I don't think it has anything clear to say about whether increased VO2Max helps BH):
https://scholars.direct/Articles/sports-medicine/aspm-1-004.pdf
Finally, it's probably worth noting that VO2Max has been discussed here in the forums before (back in the day when there were a lot more of the big-name freedivers active in here). For example...
I want to know if somebody has any experience with this: Is the Vo2 max a good predictor of static apnea time, depth in Constant ballast or distance in dynamic? I read that Martin Stepanek has a Vo2 max of 54.7 ml/kg/min Mandy Rae Cruickshank of 49 and Brett LeMaster of 67. Does anybody...
Time vs. apnea ability? I know that a big part of this sport is mental, but I was wondering how strong the link is between cardio ability and apnea times? I can run about a 50min. 10k (not exactly world class, but about 10 min. better that I was a few years ago) My best static time is 4:34...
Lately I have been very frustrated because my static is decreasing a lot. When I first started freediving I got to 4:00 pretty quickly, and gradually increased it to 4:30. I could always get to 3:00 and on a good day 4:00 was not too hard. then I started diving a ton and didn't really worry...
Overall, it does seem to suggest there is a distinction between aerobic exercise (where VO2Max would become more important) vs anaerobic (which would have more of a bearing on BH, hypoxic & hypercapnic tolerance, etc.)
My own take on it would be (and this is simply from some degree of common sense combined with above) that you shouldn't be trying to minimise VO2Max to improve BH (I mean, becoming really unfit isn't gonna benefit BH!), but rather that there comes a point where specifically trying to increase VO2Max doesn't provide that much further benefit for BH (and could even potentially harm it a bit, if some of above comments are to be believed...)
Anyway, hope that's interesting!