VO2 training percent

I can’t find the answer in my forum searches… I know the podcast talked about it some time ago, but I also can’t find that either.

I’m just looking for the effects of training VO2 at 120% versus 110% or any other percent in the VO2 range. Does it really matter what percent I’m at as long as I am hitting the physiological response?


Following this as it’s something I was mulling over yesterday. I was thinking to myself why go 5% harder if the gain is marginal from say 120 to 115.

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Enjoy the deep dives:


And if you really want to know the answer…

(start @ #18)


Love the no spoilers style :grinning::grinning:

The lower the %, the longer it takes to reach VO2max, thus an overall decrease of time in zone.

As for me, I’d rather hit the target watts and reduce overall interval length to 2.5 minutes from 3 min. I feel I still get the “minimum effective dose” that Chad mentioned in recent podcasts while burning fewer mental matches.

I don’t get same mental effect if I decrease % and stick to 3 minutes. YMMV.

Well for starters % FTP for vo2max workouts is highly individual, unlike using % for workouts below FTP.

So right away it’s hard to say what the impact is for YOU at this particular time. For example there have been times when 112% gives me a strong stimulus, and other times like this spring I used 122% for 3-minute vo2 intervals. At least for me it’s both trainable and depends on current fitness level.


If you’re not used to exercising, then even exercising at 60% of VO2max represents an overload.

If you’re used to exercising at 60% of VO2max, then you need to exercise at (say) 70% of VO2max to create an overload.

If you’re used to exercising at 70% of VO2max, then you need to exercise at 80% of VO2max to create an overload.

If you’re used to exercising at 80% of VO2max, then you need to exercise at 90% of VO2max to create an overload.

If you’re used to exercising at 90% of VO2max, then you need to exercise at 100% of VO2max to create an overload.

So, how fit are you (and how badly do you want to improve)?

I find doing 1 minute intervals at 100% of FTP to be much easier mentally. Problem is, they don’t seem to work. Why is that?

Just like a VO2 interval, ya gotta work for it! :rofl:

Basically, VO2max is a physiological phenomena, not a power target; thus training by power is less accurate than training by physiological metrics (HR, inspiration), which are a bit more accurate.

Unless you’re hooked up in a lab, you’re not going to know your exact %FTP when you enter VO2max; 120% is used for a general population average.

Prescription to cure this conundrum:
Start hard enough to jack up your HR, then ease off the gas a bit so you don’t blow up, hammer until the end. Rest. Repeat.




VO2max is a physiological state.

You can’t improve VO2max, or power at VO2max, without spending time at VO2max.

This was exactly what I was going to do. I can suffer quite spectacularly just a few percent lower and actually complete the workout.

I just want to go through the rest of my day feeling as kickass as if I did the workout at the prescribed % when it comes to vo2.

Another question… Can I apply this same thought process to the supra-threshold ranges?!

I think people get confused when “VO2max is a phsyiological state” is thrown around.

VO2max is maximum aerobic capacity. There are two major components to your aerobic capacity:

  • ability to transport oxygen from lungs to muscles via the heart and bloodstream
  • ability of the muscles’s mitochondria to receive and use the oxygen

you can improve vo2max by doing long duration / low intensity rides.


Yeah, I think there’s enough individual variation with v02max that your best bet is just to base your adjustments off feel/experience. A properly executed 3 minute interval is fairly unmistakable, so I usually just try and pinpoint the “hello darkness my old friend” moment.

If you can’t complete workouts I would adjust them down a few percent for sure, but I wouldn’t be doing so with the aim of making them more comfortable or less fatiguing. v02max intensity is by nature a pretty unpleasant experience.

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Worth listening to the Podcast No.273
Or watching this:

Really useful understanding of VO2 (Aerobic Capacity) and how to train it.

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Only if you are already very fit.

For example, back when I was racing and being tested regularly, I could get within about 5% of my apparent genetic maximum while never training above threshold.

“The ACSM considers 50% of VO2R to be a threshold intensity for most clients and 40% to be the threshold for those with very low fitness.”

50% of VO2R(eserve) would be between 50 and 55% of VO2max for most people.


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This is just not true, I know someone will have already have pointed this out but I felt that this untruth was worth pointing out again. :wink:


There seem to be a lot of untruths accepted as gospel on this forum. It’s like nobody has ever taken an ex fizz class.