VO2 max..

Eve1972

So I finally got around to doing the vo2 fitness test on my Polar and it gave me a number of 41 which is "very good". I thought cool, and figured my calorie burn would go down a bit, well much to my surprise I burned 200 more calories doing the same workout! Someone please explain to me how this is possible, because 200 calories is a pretty large amount! *lol*

kenlad64

Great question, great number, when I got mine at Christmas I got a 42 for my vo2 max, I gotta re-check mine and see if I am getting any better. I am interested in the response to your question, ....and yes, I agree that is a very good number.

Martucha123

the bigger your VO2 max, the more calories you burn at the same HR
In other words: if you are not fit, then your VO2 max is lower, but your HR while you jog goes way higher
if you are fit then your HR does not go that high while you jog,

I assume you have adjusted your VO" max and now your HRM is showing the right burn.

exemple:
my VO2 max a motnh ago was 35,5 and after one mile jog my HR would be 183,
now my VO2max is 38 and my HR after 1 mile jog is 175.
I burn less cals now, but if I jog faster (say I jog for the same 10 minutes but the distance will be 1,25 mile) and make my heart go to 183 then total burn would be higher.

BrianSharpe

Your VO2 Max is an indicator of cardiovascular fitness and endurance, your HRM calculates your calories expended as a function of heart rate, body mass and time. Has your resting heart rate gone down much? Is your average heart rate while exercising going down?

I'd suggest there would be more of a correlation between those and you calorie burn than with your VO2 Max.

icemaiden17_uk

Bumping because I'm interested!!

Martucha123

Your VO2 Max is an indicator of cardiovascular fitness and endurance, your HRM calculates your calories expended as a function of heart rate, body mass and time. Has your resting heart rate gone down much? Is your average heart rate while exercising going down?

I'd suggest there would be more of a correlation between those and you calorie burn than with your VO2 Max.

some HRM use formula that include weight, hight, age, VO2max and HR.

Eve1972

Interesting, because I always though the better your VO2 was the less calories you would burn, confused! *lol* My resting heart rate has gone down, it is 55 now, use to be 65..thanks to everyone for taking the time to reply!

BrianSharpe

Interesting, because I always though the better your VO2 was the less calories you would burn, confused! *lol* My resting heart rate has gone down, it is 55 now, use to be 65..thanks to everyone for taking the time to reply!

Here's a thought, is it possible that with your improved fitness that you're actually exercising more intensely to stay in the same zone? That would account for keeping your burn pretty much the same.

Have you lost weight and not changed the settings on your HRM? That too would result in the calories expended being slightly overstated.

That's a good improvement in resting heart rate, you've obviously been working very effectively!

Eve1972

I update my settings every week, basically the only thing I changed was to take the VO2 test on my Polar this weekend and set the VO2 with the 41 they gave me. It kind of makes me wonder what they use as a setting if you don't input that info?

Martucha123

I have read somwhere they use 35
as it seems to be the average,
but as it's confidential info,no way to be sure it's truth

Eve1972

I guess I will have to eat more food! *lol* 200 is a crazy amount more to burn though...

solpwr

I track vo2 max carefully. As it increases, your resting HR decreases. During exercise, with an increase in VO2 max, your average heart rate should be lower at the same perceived exertion level. Put another way, at the same average HR, your perceived exertion level should be lower. Simply, it's easier to do the same exercise because your body is more fit, and it is working more efficiently.

When our bodies work more effiiciently, it burns less fuel (calories) for a similar amount of work. So if average HR for the same exercise are equal, a higher VO2 max will result in less calories burned. HST, it should be harder to keep your average HR where it was when you started, with a lower VO2 max.

Remember that our bodies are constantly changing in subtle ways. My vo2 max was 38 a year ago in March. I rode my bike and was very active, and by October it was 50. The change was progressive. My diet also influenced it, and alcohol consumption had a big impact on it.

I slacked off quite a bit starting in December through February, and am just getting going again. My VO2 max is now 42.

All the while my RHR went from 58 down to a low of 38 at the lowest. Now it's 52.

Also note that how you categorize your fitness level on your Polar for the fitness test has a big influence on your number so you have to be honest with yourself. How many hours per week of cardio for the last 3 months is the criteria.

Eve1972

I have my fitness level set at moderate, I work out 5-6 days a week.

edited: I think I misread your post at first..

solpwr

I have my fitness level set at moderate, I work out 5-6 days a week.

edited: I think I misread your post at first..

You should probably choose High if you've been doing that for the last 3 months.

My choices in my HRM (Polar S710) are Low: not regular exerciser.
Middle: 2 hours cardio per week.
High: 3 hours cardio per week, 3 training sessions per week.
Top: 5 hours cardio per week, 5 training sessions per week.

I had to downgrade from Top to High since I slacked off. Hope to be back to Top in June.

shockedsoshocked

So I finally got around to doing the vo2 fitness test on my Polar and it gave me a number of 41 which is "very good". I thought cool, and figured my calorie burn would go down a bit, well much to my surprise I burned 200 more calories doing the same workout! Someone please explain to me how this is possible, because 200 calories is a pretty large amount! *lol*

What was your actual workout? There's plenty of factors that can affect HR giving you a different reading, not just changing your VO2 Max.

I don't know how putting your VO2 Max will affect the formula, I'll try to find out.

fteale

How do you calculate it with a HRM? I would love to know mine, but I have no idea where to start.

staceyseeger

I have an appt on Saturday for V02 testing...very interested in results.

LilacDreamer

How do you calculate it with a HRM? I would love to know mine, but I have no idea where to start.

this. i have a polar ft7 so i dont think i can do it

solpwr

Some Polar models have a Fitness Test feature. It measures R-wave to R-wave variability at rest and uses a proprietary algorithm to predict VO2 max. It is supposed to be reasonably accurate.

The FT40 is the least expensive model with the feature i believe.

solpwr

Google "Polar Fitness Test".

Lena1967

Bump.

Azdak

Your VO2 Max is an indicator of cardiovascular fitness and endurance, your HRM calculates your calories expended as a function of heart rate, body mass and time. Has your resting heart rate gone down much? Is your average heart rate while exercising going down?

I'd suggest there would be more of a correlation between those and you calorie burn than with your VO2 Max.

VO2 max has EVERYTHING to do with calorie burn. It represents the "scale" upon which everything else is based.

All of the mathematical gyrations that HRMs perform are an attempt to estimate VO2, since they cannot actually measure anything except heart rate.

Azdak

Just to clarify a few things in this discussion.

VO2 max represents the maximum amount of oxygen your cardio system can deliver to the body. VO2 refers to any submaximal level of oxygen uptake.

Oxygen is combined with fuel to release the energy that fuels our bodies. When this occurs, a fixed amount of heat is given off. That heat is termed a "calorie". As mentioned, a relatively fixed amount of heat is given off when oxygen is consumed, so if we know how much oxygen is being consumed, we can indirectly measure how many calories are being expended.

Maximum heart rate is the fastest one's heart can beat. Working at 100% of HRmax is equivalent to working at 100% of VO2max. The percentages are not equal (i.e. 70% of HRmax does NOT correspond to 70% of VO2max), but there is a relatively fixed relationship between relative heart rate and VO2 during steady-state aerobic exercise. In other words, if one is exercising at a heart rate that is 70% of HRmax, we know that they are working at approximately 57% of VO2max.

So if you know a person's VO2max is 40, for example, and you know that they are working at a heart rate that is 70% of HRmax, you can estimate that the VO2 for that activity is (40*57%) or about 23. Once you know VO2, it is relatively straightforward to calculate an estimate of calories burned.

That is a very rough and overly-simplistic explanation of how HRMs work. Because HRMs do not directly measure calories but try to "infer" the calories being expended via related measurements, the accuracy of HRMs is enhanced by including other factors such as age, resting heart rate, gender, height and activity level. However, those other factors do not necessarily make HRMs MORE accurate than other calorie-estimating methods--it just makes them more accurate than other HRMs.

It's important to restate that point because too many people mistakenly think that because "an HRM measures YOUR individual heart rate, it is the most accurate". The truth is that HRMs MUST use those other factors because their measurements are SO indirect. If you have a reliable estimate of the energy cost of an activity, you don't need any of those other factors--all you need is intensity and weight. You don't even need heart rate.

Many/most pieces of fitness equipment do not accurately estimate the energy cost of the work you are performing (exceptions are treadmills and some cycle ergometers), and many exercise activities consist of changing movement patterns, so there is no way to estimate VO2 from the activity alone. In these cases, a properly set up HRM can provide the "best guess" of calories burned.

If you set up an HRM with the correct resting heart rate and the correct HRmax, the HRM can calculate that the heart rate it measures during a workout represents "X" percent of your HRmax. But without knowing VO2max, the question for estimating calories becomes "X percent of what?".

To go back to our earlier example, we know the person is working at 70% of HRmax, and that 70% of HRmax is equal to 57% of VO2max. If VO2max is "unknown", then the question is "57% of WHAT?"; and if we don't have a number for "WHAT", we cannot estimate calories burned.

A HRM will come with a calculated VO2max. I have no idea how they derive the number. Some Polar models (FT40, FT60, a couple more high-end models) allow you to manually enter VO2max, if you know it.

Other Polar models have a "fitness test" which measures your resting heart rate and correlates that to a fitness level. Polar claims that the fitness test is "85% accurate". I don't have time to go into that in more detail, just suffice to say they have a method that might give you are more accurate VO2max number to program into the HRM.

So, back to the original question: why would an increase is VO2max result in an increase in calories burned for the same workout?

You may have figured this out by now. The higher VO2 number means there is now a bigger "scale". To use our earlier example yet again, we said that someone with a VO2max of 40, working at 70% of VO2max would have a VO2 of roughly 23 when doing a particular activity. Let's say that person measured their VO2max and it turned out to be 50, not 40. They are still working at 70% of HRmax, which corresponds to 57% of VO2max, but now it is 57% times 50, not 40, so the VO2 is 28.5, not 23. That would represent a 24% increase in the calories burned on the display.

Keep in mind that the change in this case did not come from a change in the person's fitness level. The change came because the OP got a different measurement that the default number in the HRM and changing that changed the calculations.

But it works similarly in real life as well. Remember: heart rate represents a RELATIVE indicator of effort--i.e. heart rate signifies that you are working at a PERCENTAGE OF MAXIMUM. VO2 represents a FIXED measure of effort--i.e. the oxygen uptake for a given submaximal workload DOES NOT CHANGE when your fitness level improves. It FEELS easier because your VO2MAX HAS INCREASED, and the heart rate for that workload will decrease because it is now a smaller percentage of your max, but the energy cost stays the same.

A common unit of aerobic intensity is called a MET (metabolic equivalent). It is equal to 3.5 mlO2/kg body wt/min. METs are used because it is easier to say the intensity of an activity is "5 METs" rather than "17.5 ml/kg/min".

So, for example, running 6.0 mph has an energy cost of approx 10 METs. That's a relatively fixed cost, regardless of who is doing the running, and whether or not you are running that speed today or a year from now.

If your VO2max today is 12 METs, then running at 6 mph would represent an effort of about 83% of your VO2max--that's a very hard effort and it would feel very hard.

However, let's say that with training you increased your VO2max to 15 METs. Running 6.0 mph is STILL an effort of 10 METs--that doesn't change. However, now that 10 MET effort only represents 67% of your VO2max. It will feel significantly easier.

Since heart rate reflects the PERCENTAGE of your maximum, the heart rate for a 67% effort will be LOWER than for an 83% effort. That does not mean you are burning fewer calories, however, because the cost of running 6 mph is still 10 METs.

If you do not adjust your HRM, the HRM will give you a lower calorie reading. Why? not because you are burning fewer calories, but because it still thinks your max is 12 METs and now it thinks you are working at 67% of 12 METs, not 67% of 15 METs.

This is a huge misunderstanding that is rampant, not only on MFP, but even with many personal trainers. They mistake the "mechanical error" of an HRM with a physiologic change that does not exist. It is testimony to the grossly misplaced belief that HRMs are somehow directly measuring calories, when in fact they are just dumb tools, programmed with pre-set responses to certain data inputs. HRMs calorie readouts are a classic example of "garbage in, garbage out".

Eve1972

Thanks again everyone, and thank you Azdak, it took me a few reads, but I think I understand it better now! To those that asked, my Polar model allows me to take a Fitness Test to determine my VO2 Max, it may also allow me to manually input it, but not 100% sure on that.

Azdak

Thanks again everyone, and thank you Azdak, it took me a few reads, but I think I understand it better now! To those that asked, my Polar model allows me to take a Fitness Test to determine my VO2 Max, it may also allow me to manually input it, but not 100% sure on that.

I believe the FT40 is the same as the FT60. If you know a specific VO2max number, you can input it manually.

First you have to take the Fitness Test. When the test results are displayed, it asks you if you want to accept the number. If you press "no" instead of "yes", the screen comes up to input your VO2max number.

I am pretty sure you have to take the fitness test first to set to the manual input screen.

solpwr

Thanks again everyone, and thank you Azdak, it took me a few reads, but I think I understand it better now! To those that asked, my Polar model allows me to take a Fitness Test to determine my VO2 Max, it may also allow me to manually input it, but not 100% sure on that.

You would do well to use the Fitness Test result as your VO2 max input unless you have a very good basis to over ride it. You can have your VO2 Max measured for a couple hundred bucks. Start with a cardiologist. They can point you in the right direction. I'm having mine measured this summer.

vs1023

Very interesting. This was a great read. I know I need to re-do my fitness test with my FT7 because last time I used it was before I got pregnant and I am not in that shape right now. Great read, lots of great info..thanks so much!

victoria4321

my ft60 has something called ownindex and I think its related to VO2 max, but I'm not sure. Mine is 45 now and when it gets higher, I burn fewer calories.