VO2max workout when tired?

Training
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Hi there,

I am wondering if it is still effective to do VO2max workouts when you are tired.

I follow a three week on/one week off plan and I do a 5x4mn@120% workout every week. On week 1, HR usually goes nicely up to 98% of max HR and 96% of HR reserve during this workout. HR doesn’t go as high on week 2 but still reaches a good 96% of max HR and 95% of HR reserve.

On total, this workout usually allows me to spend solid time near VO2max, about 12mn on week 1 and 10-11mn on week 2.

But on week 3, even though I can still push the required power, I rarely get to 90% of max HR, let alone HR reserve…

Hence my question. Is it still effective to do this workout if HR doesn’t get near VO2max ? Or maybe it is time to switch to a 2 week on/1 week off schedule (I am getting close to 50 yo) ? Or even have a look into the 9 day week ?

Thanks very much for you feedback on this.

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It depends.

What other stressors in your life could affect it?

  • sleep
  • nutrition
  • fueling before, and on the workout
  • ambient temperature

What is your age? Older athletes might need more recovery.
What else are you doing (training) in the 3-week cycle.

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OP gave that info

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Your HR is not a reliable indicator of achieving vo2max.

Reaching 90% or 95% max aerobic consumption is better monitored by breathing rate/feeling. If you have accurate W’ and FTP/CP then looking at that can also help triangulate if you achieved a high % of max aerobic. With enough max/near-max efforts a tool like WKO5 can also help.

Monitor your breathing.

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Pierre I know there’s a lot of hype around VO2Max with Peter Attia and Garmin. I do not discount that VO2Max is an indicator of overall health, longevity and generally performance. Being completely honest, from my perspective, it’s overblown. Specifically to your question doing it as often as you do and when your HR isn’t coming up, I would argue you are doing your self a dis-service. I’m not sure the big picture for you, but answering your question directly based on the limited information I have… no, you should not do it when you’re tired and HR isn’t responding.

Sorry if this comes across as anti-vo2 max work… I’m NOT. But, again, I think it’s over emphasized. Happy to answer any questions.

2 Likes
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@WindWarrior : Hi, thanks for the reply. Could you please explain how you evaluate aerobic consumption with CP and W’, or direct me to resources that does ? I am not familiar with these metrics.

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@ Power2Tri_Endurance : thanks for your message. I have been doing VO2max work (once a week) at the end of the build phase for a few years now, before I switch to long tempo and sweet spot stuff. I usually start with 8-10x1mn in January, then 6-8x2mn… until I get to 5x4mn in March. This year is the first one I noticed HR can’t keep up anymore, and I thought it was age related.

My HR data have been pretty constant for 8 years (max HR, resting HR, HR zones, VO2max, HR @ VT1 and VT2…) despite getting older, and I’ve alway thought VO2max work played a big part in that.

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Hi Pierre! As I said, I don’t have the full picture. I incorporate a fair amount of VO2Max work, as well. I was trying to make two points:

  1. You don’t need to chase VO2 Max work
  2. If you are fatigued by evidence of not being able to get your HR up, then I would do other work. It doesn’t mean you can never do it again. It’s just a sign the stimulus should change.

That said, the HR could be a few things:

  1. Fatigue (working assumption)
  2. Dehydration or Electrolyte imbalance
  3. Low carb availability
  4. Higher than normal stress

It doesn’t hurt to take a week off from VO2Max, get some solid recovery and try again.

Good luck, sir!

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That , or low(ish) vit D3 levels. It might sound crazy especially that most of us here are outdoor sports oriented and might get enough suntime , but it happened before for athletes to dip significant levels of D3 in the winter. I’d aim for at least 50 ng/ml for athletes as some sources inform here a link to some studies