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Calculate your VO2 Max

Old 01-29-24, 12:15 AM
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Calculate your VO2 Max

Found this in the book by Joel Friel, Fast After 50

Take your maximum heart rate and divide it by your resting heart rate. Take the result and multiply by 15 to get your approximate value. Only tests in a lab can reveal your true VO2 Max.
Mine is (191/55)X15=52. This puts me between a 13 and 29 YO. That must explain my childish nature.

Find your approximate fitness age in his chart below for NORMAL (read: non-athletic) individuals. Note: there is overlap between age ranges.



So what does that tell you? Your approximate fitness age compared to non-athletes.

All I know is that there is no way I could compete with any kid older than 13 or 14. For added perspective, my FTP is 228.
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Old 01-29-24, 04:47 AM
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That formula puts me at sound 46, which is more or less in line with other estimates I get from Fitbit (43-47), Garmin (50) etc. My FTP is currently around 290W or 3.6 W/kg. Call me Mr Average.
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Old 01-29-24, 08:38 AM
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50 for me at age 67. That's a few points higher than the performance-based estimates from HRV4training and intervals.icu, but I'll take it.

Incidentally, the measure is in ml/kg/min, so the formula really should take body weight into account.

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Old 01-29-24, 08:53 AM
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If you know what you currently are, then you can use it to let you know if you are getting better when you compare it to what ever value you get in the future. But since I tend to ride the same routes, time alone lets me know I'm better.
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Old 01-29-24, 09:40 AM
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Hmm.
  • Friel method: 59.3
  • Garmin: 54 55
  • HRV4Training: 57.6
All within a reasonably sized imaginary ballpark.

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Old 01-29-24, 09:57 AM
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Age 53, near 54.

VO2 max estimates:
Friel method: 64
Garmin: 60-63 depending on the week

Current measured FTP~4.0 W/kg (280W @70kg)
Haven't had a lab test in a few year years, but have one coming up. I have a cardiac electrical issue (LBBB) that doesn't affect my heart rate, but significantly decreases stroke volume, filling efficiency, and overall output killing my high end endurance power, so the formulas don't don't work as well on me.
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Old 01-29-24, 10:15 AM
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Friel drives me nuts.
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Old 01-29-24, 04:38 PM
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Resting heart rate just before I get out of bed in the morning? Or resting HR mid-day sitting down for 5 minutes? Can I breathe deeply for 5 min ahead of the reading?


is this formula even valid for folks with any heart issues? Not serious, but I have mild LBBB and low resting heart rate. Believe me - I ain't no teenager these days. But I have always had a large tidal volume (and a big nose for free air!).
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Old 01-30-24, 05:01 AM
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Originally Posted by PeteHski
That formula puts me at sound 46, which is more or less in line with other estimates I get from Fitbit (43-47), Garmin (50) etc. My FTP is currently around 290W or 3.6 W/kg. Call me Mr Average.
I'll call you Mr Humble.

At least here in 'Murica, there is nothing average about a 50+ year old with a 300w+/- FTP. The typical fitness metric used here would be BPH - Beers Per Hour. Or WPH - Wings Per Hour.
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Old 01-30-24, 08:02 AM
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Originally Posted by Jughed
I'll call you Mr Humble.

At least here in 'Murica, there is nothing average about a 50+ year old with a 300w+/- FTP. The typical fitness metric used here would be BPH - Beers Per Hour. Or WPH - Wings Per Hour.
Cheers, good point! It's much the same over on this side of the pond. The average couch potato is not very fit. Poor diet, minimal exercise, poor lifestyle. I meant average in terms of my genetics. 4W/kg is about my FTP limit when I'm well trained. Pushing above that point always seems out of reach. Where I am now is about my baseline, which I can maintain with a bit of effort.
My peak estimated VO2 max (Garmin) is in the low to mid 50s. My resting HR drop to around 58 and my max HR is around 193. So Friel's formula would put my VO2 max at 50. Close enough.
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Old 01-30-24, 08:05 AM
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Garmin puts me at 55. The formula says 47. At 72 years old I figure that isn't too bad, but not conviced it means much maybe because "NORMAL" means sedentary. Still I'll take it as a positive since I probably would have been a lot closer to "NORMAL" 2-3 years ago.

I can understand folks my age being out of shape knowing how many aquaintances have heart and other health issues, but if the chart is correct it is sad for some of the youngsters in the chart.

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Old 01-30-24, 08:19 AM
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Originally Posted by Wildwood
Resting heart rate just before I get out of bed in the morning? Or resting HR mid-day sitting down for 5 minutes? Can I breathe deeply for 5 min ahead of the reading?


is this formula even valid for folks with any heart issues? Not serious, but I have mild LBBB and low resting heart rate. Believe me - I ain't no teenager these days. But I have always had a large tidal volume (and a big nose for free air!).
How you take resting HR could make a big difference. My Garmin is on all night and I just use the number it chooses. That seems to be close to but not the very lowest HR overnight. Not sure how they determine it. I have just trusted that number. Back in the pre garmin days I tried to read my pulse upon waking before moving.

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Old 01-30-24, 08:36 AM
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Originally Posted by PeteHski
Cheers, good point! It's much the same over on this side of the pond. The average couch potato is not very fit. Poor diet, minimal exercise, poor lifestyle. I meant average in terms of my genetics. 4W/kg is about my FTP limit when I'm well trained. Pushing above that point always seems out of reach. Where I am now is about my baseline, which I can maintain with a bit of effort.
My peak estimated VO2 max (Garmin) is in the low to mid 50s. My resting HR drop to around 58 and my max HR is around 193. So Friel's formula would put my VO2 max at 50. Close enough.
I hope to see 4W/kg at some point!!

Friel has me at 50.5 (172/50), the last Garmin reading had me peak at 47 at the end of my training last spring. (For whatever reason, I just don't use my HR monitor unless I'm doing training blocks) I'm down about 5.5kg since that time and my power has gone up, so the 51 makes sense.
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Old 01-30-24, 09:02 AM
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According to Friel, I'm at 52.85. I haven't taken the test/looked at it on my Polar watch. I guess I should. It might change if weight was taken into account. On a non serious note though, my hair keeps thinning as I get older. I'm dissappointed that my V05 max keeps going down. One of these days it might be at zero.
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Old 01-30-24, 09:20 AM
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Originally Posted by seypat
According to Friel, I'm at 52.85. I haven't taken the test/looked at it on my Polar watch. I guess I should. It might change if weight was taken into account. On a non serious note though, my hair keeps thinning as I get older. I'm dissappointed that my V05 max keeps going down. One of these days it might be at zero.
You will have a lot of company because, one of these days, all of our will be zero. 👼
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Old 01-30-24, 09:21 AM
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Does calculating VO2 Max from RHR and MHR actually make sense and work? I know that there are a few guys in the pro peleton that have really low MHRs. I am sure they must have high VO2 Max to make in in the pro peleton. Can they possibly have a low enough RHR for the calculation to work for them? Or are they outliers where the calculation doesn't work?

On the other end of the scale are those of us with much higher than normal for our age MHR calculating inaccurately high VO2 Max numbers? I mean, sure I like patting myself on the back for that "superior" number, but I am suspicious of it.
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Old 01-30-24, 11:52 AM
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Originally Posted by staehpj1
Does calculating VO2 Max from RHR and MHR actually make sense and work?
Well, *mostly* all you need to really know is that cardiac stroke volume for the kinds of guys that would read Friel's "Fast after 50" book is ballpark about 70 mL of blood per beat, assuming average ejection fraction. Then, cardiac output is just stroke volume * beats/minute, so if you know your max heart rate you can approximate your max cardiac output. (Resting heart rate helps a tiny bit because lower resting heart rates are associated with slightly higher stroke volume, but this is a relatively small effect). If you don't have some disease that affects the oxygen-carrying capacity of your blood (and once again, guys who're reading "Fast after 50" probably don't) then the amount of O2 being carried by the blood and the amount that it can deliver to muscles for usable work is also ballpark known. So, for each 100 mL of blood at max cardiac output, you can carry around 5 mL of O2. So you can kinda get from max HR to max O2 your heart can deliver to your muscles. So you can sorta kinda get to VO2Max in terms of Liters/minute. I think most of the guys reading "Fast after 50" aren't going to be 50kg or 150kg, so maybe 70 or 75kg puts his readers in the right ballpark.

So there's some (that is, a lot) of hand-waving going on but I can sorta trace back where Friel's rule of thumb comes from, and, importantly, the error bounds on his rule of thumb. (I teach a lot of rules of thumb to my students, but I go through the derivations so they can see what and where I'm making assumptions and which ones are more critical and which are less so. Friel drives me nuts cuz he doesn't do this, and it offends my sense of pedagogical fidelity).

You can do better by measuring power, but many of the readers of Friel's book (at the time of publication) probably didn't have a power meter. [Edited to add:] At average levels of cycling economy, it takes in the ballpark of 1 L of O2 per minute to produce 75 watts for a minute, so it takes around 3 L of O2 to produce 225 watts (or 4 L to produce 300 watts). So the (slightly better) way to calc your VO2Max from power data is to figure out your max sustainable aerobic power, convert that to an approximate volume of O2, and estimate your VO2Max that way. You don't really need to know HR that way at all. That said, VO2Max isn't a particularly actionable piece of information.]

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Old 01-30-24, 12:27 PM
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Originally Posted by Wildwood
Resting heart rate just before I get out of bed in the morning? Or resting HR mid-day sitting down for 5 minutes? Can I breathe deeply for 5 min ahead of the reading?


is this formula even valid for folks with any heart issues? Not serious, but I have mild LBBB and low resting heart rate. Believe me - I ain't no teenager these days. But I have always had a large tidal volume (and a big nose for free air!).
Good question!

If I take my historical minimum and maximum heart rate, the result is a ridiculously high 77, but if you take my average resting heart rate, the result is 57.8.

Also, my iPhone (using the same data, presumably), calculates my VO2 max at a bit over 32, and tells me that is above average for people my age. I am thinking that general formula is ... well ...

BTW: My uptake is also improved by a custom proboscal intake of enhanced size (big schnoz).


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Old 01-30-24, 01:59 PM
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Originally Posted by staehpj1
How you take resting HR could make a big difference. My Garmin is on all night and I just use the number it chooses. That seems to be close to but not the very lowest HR overnight. Not sure how they determine it. I have just trusted that number. Back in the pre garmin days I tried to read my pulse upon waking before moving.
. By that formula, for me - (155/38) 15 = I'm a teenager again, at age 72 7/12 years

this thread is good and the formula is an excellent demonstration of how things only apply when everything outside the narrow parameters are equal (which is frequently never, esp in older humans).


kinda like taking a maximal 20min effort times (~~90%-95%) to shortcut the measurement of sustained power for an hour. Not the same.

or

fat tires and low tire pressure make pavement bikes faster......

or

wide handlebars open one's chest for better breathing and enhanced aerobic performance & greater speed.

or

"this frame is 5% more vertically compliance and 3% more torsionally rigid than last year's frame", so one will ride faster more comfortably buying a new frame every year, forever.

or

fill in one's favorite pet peeve cycling data truism.
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Old 01-30-24, 03:25 PM
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Originally Posted by RChung
You can do better by measuring power, but many of the readers of Friel's book (at the time of publication) probably didn't have a power meter.
I'd think that many still don't. I know that I don't. I mostly ride mountain bike so maybe that might make me a little less likely to have one. Or maybe I am cheap, or just old fashioned?

I am 72 and no longer a racer. I might race again at some point for the fun of it, but I am certainly not serious about it. Power data would be interesting, but I am not inclined to plunk down the $$$. These days while I ride every day I really don't worry about maintaining a competetive edge. Watching the minutes in the various zones is probably enough data for me.
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Old 01-30-24, 04:02 PM
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Originally Posted by staehpj1
I'd think that many still don't. I know that I don't. I mostly ride mountain bike so maybe that might make me a little less likely to have one. Or maybe I am cheap, or just old fashioned?

I am 72 and no longer a racer. I might race again at some point for the fun of it, but I am certainly not serious about it. Power data would be interesting, but I am not inclined to plunk down the $$$. These days while I ride every day I really don't worry about maintaining a competetive edge. Watching the minutes in the various zones is probably enough data for me.
To be fair, what would you do with the information on VO2Max if you had it? Especially if the estimate of VO2Max were as rule-of-thumby as Friel's?

I've had a power meter for years, and I rarely bother to check my VO2Max -- I don't consider it either a particularly actionable piece of information, nor an especially good predictor of performance. Although I have power data, basically I use a wristwatch as my indicator of performance, combined with how I feel during and after a ride.
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Old 01-30-24, 04:14 PM
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Originally Posted by RChung
To be fair, what would you do with the information on VO2Max if you had it? Especially if the estimate of VO2Max were as rule-of-thumby as Friel's?

I've had a power meter for years, and I rarely bother to check my VO2Max -- I don't consider it either a particularly actionable piece of information, nor an especially good predictor of performance. Although I have power data, basically I use a wristwatch as my indicator of performance, combined with how I feel during and after a ride.
Nothing. I don't really care too much about optimizing performance beyond the good general health and feel good riding kind of level. Why did I bother to look at the Garmin number and do the friel calculation? Because I saw this thread and was curious. It is kind of a nice "gee I am doing okay for an old geezer" kind of thing to look at and maybe follow to see if I can manage to avoid having it decline more rapidly than it should.

As I have said what I use as a guide for how I ride is more just a look at the time in zones after each ride to see if the ride was the kind of effort I was shooting for. Pretty simple and unsophisticated, but for my goals probably sufficient.
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Old 01-30-24, 04:15 PM
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At my age (of 85), I'm just glad that my heart's beating.
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Old 01-30-24, 04:59 PM
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Originally Posted by RChung
Well, *mostly* all you need to really know is that cardiac stroke volume for the kinds of guys that would read Friel's "Fast after 50" book is ballpark about 70 mL of blood per beat, assuming average ejection fraction. Then, cardiac output is just stroke volume * beats/minute, so if you know your max heart rate you can approximate your max cardiac output. (Resting heart rate helps a tiny bit because lower resting heart rates are associated with slightly higher stroke volume, but this is a relatively small effect). If you don't have some disease that affects the oxygen-carrying capacity of your blood (and once again, guys who're reading "Fast after 50" probably don't) then the amount of O2 being carried by the blood and the amount that it can deliver to muscles for usable work is also ballpark known. So, for each 100 mL of blood at max cardiac output, you can carry around 5 mL of O2. So you can kinda get from max HR to max O2 your heart can deliver to your muscles. So you can sorta kinda get to VO2Max in terms of Liters/minute. I think most of the guys reading "Fast after 50" aren't going to be 50kg or 150kg, so maybe 70 or 75kg puts his readers in the right ballpark.

So there's some (that is, a lot) of hand-waving going on but I can sorta trace back where Friel's rule of thumb comes from, and, importantly, the error bounds on his rule of thumb. (I teach a lot of rules of thumb to my students, but I go through the derivations so they can see what and where I'm making assumptions and which ones are more critical and which are less so. Friel drives me nuts cuz he doesn't do this, and it offends my sense of pedagogical fidelity).

You can do better by measuring power, but many of the readers of Friel's book (at the time of publication) probably didn't have a power meter. [Edited to add:] At average levels of cycling economy, it takes in the ballpark of 1 L of O2 per minute to produce 75 watts for a minute, so it takes around 3 L of O2 to produce 225 watts (or 4 L to produce 300 watts). So the (slightly better) way to calc your VO2Max from power data is to figure out your max sustainable aerobic power, convert that to an approximate volume of O2, and estimate your VO2Max that way. You don't really need to know HR that way at all. That said, VO2Max isn't a particularly actionable piece of information.]
Thanks for this post, I found it very interesting. As a retired engineer, I really like these types of numbers and calculations.
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Old 01-31-24, 10:33 AM
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Originally Posted by RChung
Well, *mostly* all you need to really know is that cardiac stroke volume for the kinds of guys that would read Friel's "Fast after 50" book is ballpark about 70 mL of blood per beat, assuming average ejection fraction. Then, cardiac output is just stroke volume * beats/minute, so if you know your max heart rate you can approximate your max cardiac output. (Resting heart rate helps a tiny bit because lower resting heart rates are associated with slightly higher stroke volume, but this is a relatively small effect). If you don't have some disease that affects the oxygen-carrying capacity of your blood (and once again, guys who're reading "Fast after 50" probably don't) then the amount of O2 being carried by the blood and the amount that it can deliver to muscles for usable work is also ballpark known. So, for each 100 mL of blood at max cardiac output, you can carry around 5 mL of O2. So you can kinda get from max HR to max O2 your heart can deliver to your muscles. So you can sorta kinda get to VO2Max in terms of Liters/minute. I think most of the guys reading "Fast after 50" aren't going to be 50kg or 150kg, so maybe 70 or 75kg puts his readers in the right ballpark.

So there's some (that is, a lot) of hand-waving going on but I can sorta trace back where Friel's rule of thumb comes from, and, importantly, the error bounds on his rule of thumb. (I teach a lot of rules of thumb to my students, but I go through the derivations so they can see what and where I'm making assumptions and which ones are more critical and which are less so. Friel drives me nuts cuz he doesn't do this, and it offends my sense of pedagogical fidelity).

You can do better by measuring power, but many of the readers of Friel's book (at the time of publication) probably didn't have a power meter. [Edited to add:] At average levels of cycling economy, it takes in the ballpark of 1 L of O2 per minute to produce 75 watts for a minute, so it takes around 3 L of O2 to produce 225 watts (or 4 L to produce 300 watts). So the (slightly better) way to calc your VO2Max from power data is to figure out your max sustainable aerobic power, convert that to an approximate volume of O2, and estimate your VO2Max that way. You don't really need to know HR that way at all. That said, VO2Max isn't a particularly actionable piece of information.]
I had forgotten this went back to Friel. So, why does it yield the per kg number and what weight does it assume?
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