Maintaining Vo2 max

Training
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I’m not an exercise physiologist so I apologise in advance for errors and stupidity.

Most coaches say that Vo2max is best increased via Vo2max intervals.
Some of these same coaches also say that Vo2max can be maintained via high volume low intensity base training.

The Fick equation (Fick principle - Wikipedia) can be rearranged to form

Vo2 = Cardiac Output x Arteriovenous Oxygen Difference or Vo2 = CO x (Ca - Cv)

If Vo2max intervals maximally increase Cardiac Output by increasing stroke volume, I can’t see by what logic it would make sense to say ‘Vo2max intervals are not necessary to maintain Vo2max so don’t do them during base training’ which is almost verbatim what an experienced coach said to me on the r/velo discord. I can see how ‘lots of z2’ would maintain adaptations in stroke volume to some degree and also peripheral adaptions; however the principle of specific adaptations to imposed demands (is this a valid principle?) would dictate that the adaptations in stroke volume would decrease to a level to meet the demands of ‘lots of z2’ and not maintain the previous level of ‘lots of z2 + some Vo2max intervals’.

The only related study I’m aware of is Ronnestad’s paper here: HIT maintains performance during the transition period and improves next season performance in well-trained cyclists | European Journal of Applied Physiology

I originally asked after reading Skiba’s recommendation to maintain adaptations all year round by ‘touching up’ various training zones periodically. Specifically he recommended 4 x 2’/2’ Vo2 intervals as suitable for Vo2max maintenance. Contrary to this is the convention of doing no Vo2max intervals for 3 months of the year and then working them back into the programming. But why? If it takes just ~8 minutes of Vo2max intervals every 7-10 days to maintain precious and hard won stroke volume adaptations why not just do them?

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Disclaimer: Not an exercise physiologist but am a practicing physician who studied basic physiology in med school and is generally obsessed with cycling.

I think you are getting a few things confused here. For instance, the claim that “…Vo2max intervals maximally increase Cardiac Output by increasing stroke volume…” is not really accurate. Cardiac Output (CO) is equal to Stroke Volume (SV) time Heart Rate (HR). Stroke volume increases from baseline to peak somewhere around 75% of HRmax. Above 75% HRmax, changes in CO are from increases in HR, not SV (remember, CO = SV x HR).

By training up to ROUGHLY 75% HRmax you can maximize CO (with peak SV) while keeping HR relatively low (again, CO = SV x HR). Maximizing SV at low intensities allows for this. From your heart’s perspective, this is what base training is.

What is referred to as “VO2 max” is the result of several different processes and variables interacting simultaneously, CO being one of them. Others include, but are not limited to, your blood’s capacity to carry O2 (i.e. hematocrit), the ability of your muscles to extract O2 from the blood and process it aerobically (i.e. metabolic efficiency), the ability of your lungs to extract O2 from the air (i.e. pulmonary function), the density of the air you are extracting O2 from (i.e. elevation), the ability of your nervous system to generate the muscular power needed to get to your maximal O2 consumption, your mental fortitude to ignore the alarm signals telling you to slow down, what time of day it is and how you slept the night before…You get the idea.

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Hi, thank you for the response.

I thought HR was untrainable and only left SV as a trainable input. About SV and intensity:

** Does Stroke Volume Increase During an Incremental Exercise? A Systematic Review**

Results: The stroke volume data in maximal-exercise load are inconsistent. There is evidence to hypothesis that stroke volume increases during maximal-exercise load, but other lines of evidence indicate that stroke volume reaches a plateau under these circumstances, or even decreases.

Stroke volume does not plateau during graded exercise in elite male distance runners (Jensen and Fellingham 2001)
https://www.researchgate.net/publication/11663145_Stroke_volume_does_not_plateau_during_graded_exercise_in_elite_male_distance_runners

“Results from university distance runners and untrained university students support the classic observation that SV plateaus at about 40% of maximal oxygen consumption despite increasing intensity of exercise. In contrast, stroke volume in the elite athletes does not plateau but increases continuously with increasing intensity of exercise over the full range of the incremental exercise test.”

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Another one:

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You don’t have to train at/near VO2max to increase your VO2max… unless you’re too close to your ultimate limit, in which case it may be the only way (or impossible to raise your VO2max further).

In that sense your coach is correct, i.e., you don’t necessarily have to train at/near VO2max to maintain your VO2max, at least to some degree… although obviously it would help.

The question therefore really isn’t about physiology. Rather, it is simply how much of a drop-off from peak fitness is acceptable, and what are you willing/able to do to achieve that goal?

After a few years of sufficiently intense training, VO2max will not increase further, even in elite endurance athletes. However, it will fluctuate, falling by perhaps 10% in the off-season before climbing back up again.

Without measuring their VO2max but knowing how many amateur cyclists (i.e., my competition) train(ed) and perform(ed), I suspect that most people see an even greater drop-off, and that it is too much. Not only does it mean wasting too much time getting back to where they were the year before, it probably impairs their long term progress (just as my son has left behind all his HS swimming teammates, because he’s the only one never taking an extended break from serious training).

Personally, although I was always a diligent off-season trainer, I had one of my best seasons ever after doing the following workout 3 d/wk all winter:

5 min w/u
20 min @ 275 W
5 min easy
5 min @ 325 W
2.5 min easy
5 min @ 325 W
2.5 min easy
1 min @ 500 W
5 min easy
1 min @ 500 W
5 min w/d

I called it my “90/90/90” workout because in each case the powers were (somewhat fortuitously, since I chose them by feel) about 90% of what I could do at peak fitness in-season. That made them almost maximal in the off-season.

TL,DR: I’m in favor (obviously) of doing a smattering of high intensity training all year 'round. It doesn’t necessarily have to be VO2max intervals, however… rather, it should be specific to your competitive goals.

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Not an exercise physiologist.

Doing something like a block of VO2 work can increase VO2max in the short term by like 5-10%. If you stop doing the VO2 work this seems to go away pretty quickly.

Many people find VO2 work very fatiguing, so many coaches and cyclists seems to only do it during certain periods of training, rather than year round.

Some people think that a bit of regular VO2 work through the year is fine (not a VO2 block) and do this. This is most frequently mentioned in older cyclists where there is some low-quality data that could be interpreted to suggest that doing this may slow the age-related decline in VO2max.

I am unaware of any scientific study that would allow you do say with any degree of certainty whether it was better to do VO2max work regularly or only in blocks. I think this is why you hear differing opinions - because it’s all based off anecdote mostly.

As you’ve mentioned, there is fairly robust anecdotal experience that in the long-term, volume of endurance exercise itself leads to much larger and more sustained increases in VO2max. I don’t personally think this is only from z2 volume. But rather, the more volume over the longer period of time the better, and much of this volume needs to be easy to avoid fatigue.

Despite the robust anecdotal evidence, as far as I’m aware there is only a single case report showing this though. Mostly because no one has studied this, rather than because the science shows it doesn’t happen.

Stroke volume is typically the major variable correlated with VO2max, despite the fact that as you near VO2max, further increases in CO are mediated by an increase in heart rate. Consider though that peripheral factors (ie: peripheral vascular resistance) in turn influence stroke volume. It’s not determined only by cardiac factors.

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…if you’re not sufficiently well trained to start.

As for Cousins’ anecdata (I assume that was your allusion), like 99.9% of the other crap he puts out there, I wouldn’t pay any attention to it.

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:joy:

But no I’m not talking about that, I’m talking about this one:

I’m also speaking from personal experience as when I was a power-lifter in my 20s but before I did any endurance sports I had a lab-tested VO2max in the mid-30s as part of a research study. Then in my mid-30s after cycling for a few years, I had another lab-tested VO2max in the 60s.

As far as I know, no one has studied or published anything where they follow changes in VO2max over several years when sedentary people start exercising regularly. If you know of one I’d like to see it, as otherwise anecdotal data is gonna be the best info we have to answer that specific question.

There is also some construct validity to the notion that there can be large increases in VO2max over a period of years when people are starting from sedentary, as it’s relatively common that a sedentary young person could increase their FTP from like less than 200w to 300+w… and it seems unlikely that’s all due to increases in FTP as a percentage of VO2 alone.

I’d love for someone to do this study, as you could probably take a reasonable stab at it using retrospective proprietary database data only, and in that sense, it could be a pretty easy research project.

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Thanks, I hadn’t seen that study before. I have to say, though, that the “pre” data look quite suspect - in fact, as best as I can tell, his initial VO2max wasn’t even measured, but instead just estimated using some unspecified equation.

That said, there are few other case reports out there of 50-75% increases in VO2max in previously sedentary individuals who get serious about training, and on multiple occasions I have consulted with someone who has essentially doubled their VO2max by doing Hickson-style intervals regularly (most recently, daily!) for a couple of years. However, I don’t think that a person with average genetics can do that, no matter how motivated that they might be (unless they are starting from an abnormally low baseline, e.g., from bed rest, as in the classic Dallas study).

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lol agree. I only mention it because it’s the only thing I’ve ever seen that’s tried to look at/formally document long term VO2 changes in non-elite athletes.

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Anecdotally I suspect you are right. My training age is relatively young, though i have sustained 13+ hours of riding a week via cycle commuting and mtn biking at the weekend for well over 30 years. When i regularly cycle commuted i certainly noticed my friends fitness drop away through the winter whilst i carried with my regular commute. Now I no longer have the regular commute i make an effort not to let the fitness drop too much over winter. That includes including intensity every week, and not having the volume drop too much.

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I am aware of (i.e., have read) comparable case reports from ca. 1970, but obviously it’s difficult to track such work down (again). That’s doubly so since IIRC one of the studies was published in a book or conference proceedings, not a regularly-issued journal.

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Great question @Antandron!

For what it’s worth, we recently meta-analysed the training literature comparing groups of trained athletes with varying fitness levels who trained exclusively below maximal metabolic steady state (MMSS ≈ CP, FTP, MLSS, etc.) to groups that included high intensity interval training above MMSS (“threshold”).

V̇O₂max increased significantly more in the groups training above threshold, than in the groups training exclusively below threshold. The difference was equivalent to around 2.5 ml·kg⁻¹·min⁻¹.

However, time-trial performance and Wpeak in an incremental test improved THE SAME between groups.

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This included training periods between 2 and 12 weeks, and the duration of training intervention did not appear to influence the results. These were all reported as trained athletes, so in theory we’re not just seeing the early gains of untrained individuals where anything and everything causes improvements. This is supported by the finding that training status and baseline V̇O₂max did not influence the results. Also worth noting the TT duration (from ~5 to 60 min) also did not change results.

So high-intensity training appears beneficial to improve V̇O₂max, but lower-intensity training appears sufficient to improve performance in trained athletes, at least over a few training blocks.

We can only speculate whether the additional V̇O₂max would be ‘expressed’ as additionally improved performance over longer time frames. We can also only guess whether the same would be found for preserving V̇O₂max & performance during a period of detraining or transition between seasons.

Article (free) here:
https://www.researchgate.net/publication/374091331_The_Additional_Effect_of_Training_Above_the_Maximal_Metabolic_Steady_State_on_VO2peak_Wpeak_and_Time-Trial_Performance_in_Endurance-Trained_Athletes_A_Systematic_Review_Meta-analysis_and_Reality_Check

Summary here:

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@The_Cog you’ve done work on plasma volume change influence on VO2max. What is the current thinking about training intensity-dependence of plasma vol or Hgb mass increases, and the connection from Δ plasma vol/Hgb mass → Δ stroke volume → Δ VO2max?

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I’m not sure that I understand your question?

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I’d like to tell a story about how VO2max is proportional to SV/CO which is proportional to plasma volume, and that plasma volume can be maintained by low-intensity training alone… which might be the rationale used to suggest that “VO2max can be maintained by low intensity training”.

Hypothesis related to the original question is that SV and thus VO2max might be maintained by preserving plasma vol with low intensity training alone.

I’m not sure if the current best evidence supports that story… so it’s just a story for now. You might be able to point to relevant research?

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The training-induced increase in plasma volume is due to 1) increased synthesis of albumin (and other acute phase proteins) by the liver, 2) relocation of albumin from the interstitial to the vascular compartment (Senay’s “milking the lymphatics” hypothesis), and 3) altered hormonal regulation of total blood volume, which allows you to “hang onto” that extra volume, versus just quickly excreting it.

I can’t imagine any of the above being maximized by low/moderate intensity training alone. As well, cardiac adaptations obviously also contribute to the increase in SV, and they too seem unlikely to be maximized by low/moderate intensity training.

Thus, I can’t say that I find your hypothesis plausible (unless perhaps said low/moderate intensity training was combined with another stressor, e.g., heat).

Turning it around the other way: if, once developed, a high SV/CO/VO2max can be maintained by low/moderate intensity training only, why is VO2max lower during the off-season? And why does your meta-analysis indicate that even athletes who are doing low/moderate intensity training can still “ice the cake” by adding intervals?

Maybe I have misunderstood your hypothesis?

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Thanks, yeah that all generally lines up with my understanding.

Wouldn’t say I agree with the premise that low-intensity training alone can maintain, nevermind improve VO2max/performance, but it’s a hypothesis I’m willing to think about. I’m not as familiar with the de-training literature.

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Oh man, this is interesting. So I happen to have very high bilirubin count in my blood, as did my mother. There have been shown to be some very interesting side effects of this in health terms. But now I’m reading what you just wrote…and rabbit hole continues.

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Gilbert’s syndrome?