VO2 max and max heart rate

[Streaker]

I've encountered a few questions where intensity is described as a % of VO2 max...

What exactly is the relationship between % of VO2 max and % of max heart rate when describing intensity? Also, LIP training is at around 85%MHR, what is it as a % of VO2 max?

Thanks in advance

[vexx]

I've encountered a few questions where intensity is described as a % of VO2 max...

What exactly is the relationship between % of VO2 max and % of max heart rate when describing intensity? Also, LIP training is at around 85%MHR, what is it as a % of VO2 max?

Thanks in advance

VO2 max is purely to do with aerobic system, so 100% VO2 max is the highest work aerobically, any higher and you get to the anaerobic systems, which means that 100% VO2 Max is similar (depending on person) to 85% MAX HR, so if one works at 100% VO2 max, they will be able to train to increase LIP as this is the higher aerobic point.

[lexitu]

If you look at textbooks they do not associate 85% of MHR with 100% VO2 max. For example, on Nelson page 232, they say that 85-90% of MHR is equivalent to approximately 75% of VO2 max.

[vexx]

If you look at textbooks they do not associate 85% of MHR with 100% VO2 max. For example, on Nelson page 232, they say that 85-90% of MHR is equivalent to approximately 75% of VO2 max.

that makes little sense, considering getting above 85% max heart rate is using the anaerobic systems, which means that you cannot have below 100% VO2 max, since below this is aerobic dominant... only above 100% is it non-oxygen.

[Streaker]

Here's a question (and respective answer) from the ACHPER 2009 exam (Question 4e)...

Q: Immediately upon completion of a beep test, a PE teacher instructed all students to measure and record their heart rate. A 17 year old male student who achieved the score of 14.7 recorded his heart rate at 200 beats per minute. Given this information, indicate why this student was physiologically unable to continue the beep test beyond this level.

Answer:
-He has exceeded his VO2 max
-He is working close to or at his maximum heart rate, indicating that he has exceeded his VO2 max (VO2 max approx 85% max HR)
-...therefore relying upon a significant contribution from the anaerobic energy systems and he cannot maintain this intensity due to fatigue mechanism associated with anaerobic metabolism.

[lexitu]

Working at the equivalent of 100% VO2 max. is not something that can be sustained though. It is a much higher intensity than the "aerobic zone". Otherwise, VO2 max. laboratory tests would not end. There is a high reliance on anaerobic metabolism even at this stage. These intensity figures are sometimes figurative as exemplified by a 100m sprinters heart rate during the first few seconds of the race. It would not be in the "anaerobic zone" but the intensity is what you would expect to see if you assume a linear correlation between power output and heart rate all the way to 100% MHR.

[lexitu]

@ Streaker - EDIT: I'm not sure what ACHPER is saying because it's unclear, but read below.

http://www.brianmac.co.uk/maxhr.htm - read down, try the calculator.

[Streaker]

Yeah I thought so. That's what confused me so much in the first place. Now I understand cheers

[lexitu]

Awesome. So wait, ACHPER is saying that 100% VO2 max is 85% of MHR?

[Streaker]

Yep. I copied that answer from the 2009 ACHPER exam solutions.

[vexx]

Awesome. So wait, ACHPER is saying that 100% VO2 max is 85% of MHR?

i remember doing that, we also discussed it in class to be the case..

[lexitu]

Okay well I'm pretty sure they are wrong. They are contradicting both the textbooks and brianmac. Plus it isn't logical.

[vexx]

Okay well I'm pretty sure they are wrong. They are contradicting both the textbooks and brianmac. Plus it isn't logical.

yeah i just saw that calculator so i guess i just got told wrong, but it seems illogical that its not the case.

according to that calculator 100% MHS is 98% VO2 max, but then how is it possible to get above VO2 max? Since thats anaerobic systems that is actually above 100% vo2 max, but the MHS that is anaerobic is 85%+
hmmm

[lexitu]

Yes but the heart is merely providing oxygen for the muscles (and of course for a few other things), either to use in krebs cycle and electron transport or for lactic acid oxidation. So that's where this MHR system fails. That's why heart rate monitors can only be used for aerobic training.

The calculator might be extrapolating there anyway, I'm not sure. But, 100 of VO2 max is an incredible intensity. It can't be sustained.

[vexx]

Yes but the heart is merely providing oxygen for the muscles (and of course for a few other things), either to use in krebs cycle and electron transport or for lactic acid oxidation. So that's where this MHR system fails. That's why heart rate monitors can only be used for aerobic training.

The calculator might be extrapolating there anyway, I'm not sure. But, 100 of VO2 max is an incredible intensity. It can't be sustained.

I think i understand it now, thanks.
Still not sure why anaerobic is 75% v02 max though, should it be much higher then this, as you said we can't sustain it, but 75% appears quite low..