Vo2max adoption, power or HR?

The way I simplify it:

Power is an input. If you generate the right amount of power, you can start to work at maximum aerobic capacity.

VO2 max is the result - time spent at or very close to maximum aerobic capacity.

Heart rate is the measure - it is a way of identifying if you are working close to VO2 max. It is a proxy, but it is not a direct correlation and can be influenced by other factors.

So to directly answer the OPs post, unless you are measuring VO2 max in a lab, heart rate is the better indicator. Power above threshold is used to get to maximum aerobic capacity only. 105% and 140% will both get you there in very different time frames, but you can also be at VO2 whilst putting out e.g. 50w (e.g. during the rest part of Ronnestad 30/15 intervals).

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Power is the demand, oxygen uptake is the result. HR is a proxy.

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Thanks. That helps, the final piece of the puzzle for me links back to the OPs question. Can you be at VO2 max during the early part of an interval (breathing hard) but whilst your HR is lagging to catchup (and not in VO2 max zone). Would be in VO2 power zone at that point, hence different times in zones. Interestingly I am the opposite to the OP, loads of time in power zone but not much in HR zone

I don’t think HR lags a lot if the intensity is quite hard. It lags versus power, yes, but I don’t think it lags a great deal versus actual aerobic activity. For example - if you did 2 mins at 110% ftp with a 5 min break, and repeated this 10 times, you would have 20 mins in VO2 max power zones, but likely hardly any time at all at VO2 max.

The recent findings with Ronnestad 30/15 intervals demonstrate that you can rack up a lot of time at VO2 max (HR proxy) but the intervals are well above typical ‘VO2 max’ power zone.

Personally I don’t think VO2 max should ever be used as a power zone identifier. As I said before, anything above threshold will get you to VO2 max eventually.

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So I have the complete opposite scenario.

My steady state sweet spot capacity is large. I’ve increased my hour and two hour power levels by around 30-50watts. However, the transition for me at which I can’t go on, i.e. in the ramp test is so fine it shows clearly I need to focus on my vo2, and spend lots of time there. I’ll go more based on loose power zones, as anything above 105% will ruin me over a decent amount of time.

This is a brilliant summary: The Problem with VO2max – Spare Cycles

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You need to be within at least a few bpm of maximal HR to be at 100% of VO2max.

However, just because you are within a few bpm of maximal HR - or are breathing really hard - doesn’t necessarily mean that you are at, or even close, to VO2max. This is why HR - or breathing - is only a proxy.

This isn’t true. If you are only somewhat above, or way above, threshold, fatigue will get you first. Only if you are highly motivated and exercising within a fairly narrow range of intensities will you drift all the way to VO2max.

ETA: This study illustrates things nicely. They did not determine the “aerobic limit power” (boundary between severe and extreme in their schema), but the “grey zone” went all the way up to 20% above MLSS.

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@empiricalcycling – finally finished your recent VO2 episode…question about heart adaptation vs different sport modalities (hope I can word this clearly and correctly): in the podcast you stated that using cross country skiing training levels does not translate to cycling training levels because XC utilizes more of the body than cycling, thus cycle training requires a higher degree of %VO2max to drive adaptations.

My question(s): how does muscular load/resistance affect development of stroke volume? (I think Kyle briefly mentioned this.) For example, a marathon runner is going to have a different heart structure formed by different stimulus than a powerlifter (obviously a runner will have a higher VO2max via more aerobic training). In cyclists, would a higher resistance allow us to train at a lower %VO2max (e.g. 92% instead of 100%)? In other words, does higher resistance fill in any of the deficit resulting from not utilizing the whole body (a la XC skiers)?

Bonus question: why don’t track cyclists record the highest VO2max numbers since they seemingly have a perfect combo of dynamic and static training (high load + high endurance)?

Whew. Thanks! :grin:

edit: forgot to add these:

Really not sure what you mean by higher resistance. Like more afterload?

I agree that there is a max effort (anaerobic) where if you sustain that effort you will exhaust your anaerobic capacity and not strain your aerobic system for any sustained period at VO2 max. But I’m not sure I agree that it is a narrow band - You can certainly work at VO2 doing long periods at 105% FTP, but you can also spend a long time there doing Ronnestad intervals, or even higher at 30/30s, which could be more like 150%.

Also recent studies in to hard start intervals show that you can work even higher than this to exhaust your anaerobic capacity quickly and then settle in to accumulate maximum achievable time at VO2 max.

All of this points to HR being the best easily accessible proxy for time at VO2 max, with all the usual caveats. Power is never a good proxy. Power with time is better but still not great.

I should add - I am aware you may not actually be ‘at’ VO2 max, but you are in the 95%+ range which means you are exercising it effectively for adaptation.

Muscular resistance, as in spin class or speed skating (little resistance) vs the Kilo w/ standing start or powerlifting (mucho resistance).

:man_shrugging:

Adaptations to this type of training are thickening of the heart walls (concentric hypertrophy) which does not at all help stroke volume. Discussing greater muscle use of XC skiing was in relation to increasing the muscle pump and vascular capacitance on preload.

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The average young male cyclist has an FTP of roughly 250 watts, can sprint at about 1000 watts, and can generate around 500 watts for 1 minute, which is about the minimum length of time required for VO2 to rise to maximum.

If the “grey zone” extends up to 120% of FTP, then only between 1.2 x 250 = 300 watts and 500 watts, or 20% of the total, would VO2 drift all the way to maximum. (Actually, the study set the “critical intensity” as being that which got you to 95% of VO2max, so the true range is somewhat smaller.)

Below 300 watts or above 500 watts, they wouldn’t get to VO2max (95%, actually).

From the sound of things, I think we are quite alike actually. I find sweet spot and over-unders actually quite easy compared to longer VO2max work. Mentally the most taxing bits of workouts are sprints-to-exhaustion (i. e. anything above 10 seconds).

You seem to have specialized in longer, steady state efforts, and perhaps that is exactly what you need. What do you want to get good at? Do you want to accentuate your strengths or work on your weaknesses? What kind of riding and racing do you do?

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Thanks for the reply. Don’t get me wrong - I am really happy with what I have gained: the steady-state is the main thing I need. I tend to ride long alpine days which involve long climbs, and I enjoy them the most. In normal times I would ride your standard race - over 100km, 2000+m elevation, and having a good, strong base then allows you to in principle never to be dropped, which is perfect.

My aim though really is to make my profile more versatile. I can attack (a small sprint effort) but I need to really be able to hold that power, or in the vo2 range, for a longer period of time. This would for example be an attack on a climb, hold it for 5 mins and so on. In addition, doing the ramp test is absolute killer for me. I am literally fine up until 18mins then boom, but then afterwards I feel as though “damn I could do this again” as I recover fast. I simply just don’t have that upper end.

Based on other discussions with althletes my sweet.-spot FTP is probably a good 10 watts off for effective training in that range, so it shows how blunted my profile is.

Anything you would suggest?

A cardiac output/stroke volume visual:

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This is what I was experimenting with during my last build phase, and had good results.

For two consecutive weeks I would do one session of long Vo2 intervals…started with 4x6 then went to 4x7 then 5x7 and eventually 4x8 at 105%+ of FTP

Every third week I’d do a 30/30 workout, then went down to 30/20s and was going to progress to 30x15s before moving power up.

Couple quick notes:
**I’m a masters athlete at 46y.o. - thus I do only one Vo2 workout during the week due to recovery needs/issues
**For Vo2 work I don’t use ERG and thus am shooting for maximal sustainable power over the duration of the interval…so it doesn’t map to exactly 105% or 120% exactly.
**Despite my time “in Vo2” would be nearly identical for the long interval and the short intervals, the recovery from the 30/20s was noticeably higher

Good luck🤘

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