Factors that affect resting/working HR?

agthorn

My Polar FT60 was delivered, and something is funky...

I put in all my info and did the "fitness test" (which I believe is calculating your Vo2max based on your resting heart rate?) Then I went for a 5 mile run. Nike+ app says an average pace of 10:30/mile and 492 calories burned. This is a pretty typical run for me.

The Polar said I burned 621 calories and that my average heart rate was 94% of my max! That simply can't be true - I was NOT working anaerobically for 51 minutes and I was breathing normally pretty much the entire time (about 18-20 breaths per minute, hardly panting). I could have carried on a conversation based on the "effort" rule of thumb.

So - could something have artificially affected my resting heart rate? (I've done yoga for about three years, last class was Tuesday night.) Could something have affected my working heart rate? (I lifted weights and did a session of HIIT last night - maybe my body was still in a stressed state today? I did a couple sets of pushups this morning too.)

Or am I just a freak of nature?

TiffanySuscheck

I just bought a HRM as well (not a Polar though..)

And it was telling me my highest heart rate was 210!
I don't remember having a heart attack while I was weightlifting....


I'm interested in knowing what could be wrong as well.
I plan on returning the darned thing today anyway.

agthorn

I'm not ready to send it back just yet I AM interested in teasing out what might be screwing up the calculation.

I do plan to repeat the fitness test on Monday morning and see if that affects anything.

agthorn

Someone on my news feed mentioned caffeine. I did have a cup of coffee right before I did the fitness test and within an hour of going running...

healthieryou

Did you wet it really good before you put on the strap?

agthorn

Did you wet it really good before you put on the strap?

Yep, and it was making contact and recording the entire time so I don't think it's a malfunction with the strap.

ruby_red_rose

Could you have felt a rush because you got a cool new toy to play with? That could have increased your HR by a little at least. I know my heart beats faster when I am super excited.

agthorn

Haha ruby, that's a good point too - I was super excited to get my new toy :laugh:

I am going to repeat the fitness calc first thing Monday morning. It will be before I have any caffeine and not after a lifting/HIIT day. My next run is scheduled for the 5th, which will also not be after a lifting/HIIT day (and during the week I run in the evenings, well after any caffeine intake).

chevy88grl

Someone on my news feed mentioned caffeine. I did have a cup of coffee right before I did the fitness test and within an hour of going running...

Caffeine is a stimulant and it will affect your heart rate. I know a lot of pre-workout supplements have caffeine in them. I say - give it a shot without the caffeine.

Azdak

My Polar FT60 was delivered, and something is funky...

I put in all my info and did the "fitness test" (which I believe is calculating your Vo2max based on your resting heart rate?) Then I went for a 5 mile run. Nike+ app says an average pace of 10:30/mile and 492 calories burned. This is a pretty typical run for me.

The Polar said I burned 621 calories and that my average heart rate was 94% of my max! That simply can't be true - I was NOT working anaerobically for 51 minutes and I was breathing normally pretty much the entire time (about 18-20 breaths per minute, hardly panting). I could have carried on a conversation based on the "effort" rule of thumb.

So - could something have artificially affected my resting heart rate? (I've done yoga for about three years, last class was Tuesday night.) Could something have affected my working heart rate? (I lifted weights and did a session of HIIT last night - maybe my body was still in a stressed state today? I did a couple sets of pushups this morning too.)

Or am I just a freak of nature?

The fitness test estimates VO2 max, but it does not -- and cannot -- estimate or measure maximum heart rate (HRmax). Your HRmax is set too low on your HRM.

It just so happens I addressed this very issue in a blog I posted the other day:

http://www.myfitnesspal.com/blog/Azdak/view/new-hrm-how-to-make-the-calorie-estimate-more-accurate-183102

In your case, you actually have a "baseline" that you can use for a comparison -- i.e. your Nike readings which look pretty accurate based on your weight and the energy cost of that particular running speed.

margojr4

The fitness test estimates VO2 max, but it does not -- and cannot -- estimate or measure maximum heart rate (HRmax). Your HRmax is set too low on your HRM.

[/quote]


We test Vo2max with the Rockport one mile walk. The calculation for this is crazy and can be found online somewhere I'm sure.



Max heart rate? 220-age = MHR

Then there's the Karvonen formula for your target heart rate

220-age = MHR
MHR-RHR= Heart rate reserve
HRR x % intensity = RHR = EHR (exercise /target rate)


Does the Polar ask for this calculation of your MHR?

Have fun either way with your new 'toy' lol

agthorn

Does the Polar ask for this calculation of your MHR?

It does not; I assume it's calculating it off of my info though? It asks for weight, height, DOB, sex, and a range of how many hours a week I typically work out (ranges are 0-3, 3-5, more than 5). And then the "fitness test" - which is just the unit reading your heart rate at a period of rest. The manual said to put the strap on and lie down for 1-3 minutes, then start the test while still lying down and it will receive your resting heart rate info for about 5 minutes.

agthorn

In your case, you actually have a "baseline" that you can use for a comparison -- i.e. your Nike readings which look pretty accurate based on your weight and the energy cost of that particular running speed.

Yep, my Nike+ readings are usually right around the "100 calories per mile" rule of thumb. I am more interested in the HRM for my non-running activities (my old HRM required you to input an "activity factor" in order to calculate calories burned, which I think roughly translated to METs...but if your activity wasn't on the list that came with the HRM, it was really just a guess).

agthorn

According to this site http://www.brianmac.co.uk/maxhr.htm depending on the calculation my max heart rate is somewhere between 180-192.

(Edit to add I know it's not 180 - I've had a recorded heart rate of 187 while wearing my old HRM during a kickboxing class).

tigerblue

Bump

agthorn

It just so happens I addressed this very issue in a blog I posted the other day

Thanks for the info. The FT60 does let me manually enter a VO2max number, so I will have to check the calculations on those.

Azdak

According to this site http://www.brianmac.co.uk/maxhr.htm depending on the calculation my max heart rate is somewhere between 180-192.

The problem with all of those calculators is that they have a similar standard of error--which it fairly large. It's not the fault of the researchers--it's just that there is a fairly wide spread of "normal" in the human population. Your Nike was more accurate for running because it was estimating the ACTUAL energy cost of the work--which is fairly constant. For a simple activity such as running on level ground it is easy and more accurate to measure the actual energy cost of the activity than to use heart rate.

A HRM estimates based on the relationship between heart rate and oxygen uptake (the energy cost of the activity) during steady-state aerobic exercise. If it does not have accurate heart rate information (i.e. HRmax and HRrest), then it throws the whole "scale" off and the numbers are more inaccurate.

KBGirts

Your resting heart rate will be higher when your body is recovering. So, if you had a strenuous workout the day before, your resting heart rate and your working heart rate may have been higher than normal for you during the test. I do not know the accuracy of the Polar, but maybe just trying doing the test again on a day when your resting heart rate is most likely not affected by a strenuous work out.

mhotch

When I do my fitness test I do it on the morning of a planned workout. My RHR does not immediately go back to normal after a hard workout.

agthorn

Your Nike was more accurate for running because it was estimating the ACTUAL energy cost of the work--which is fairly constant. For a simple activity such as running on level ground it is easy and more accurate to measure the actual energy cost of the activity than to use heart rate.

Completely makes sense - the only info my Nike has other than my run data is weight and sex.

Your resting heart rate will be higher when your body is recovering. So, if you had a strenuous workout the day before, your resting heart rate and your working heart rate may have been higher than normal for you during the test.

I really do think this had an effect on me today. I know that once with my old HRM, I was doing a run the day after a lifting/HIIT session and I had to run about a full minute/mile slower than I had the previous week to maintain the same heart rate. I don't normally run the day after lifting but I juggled my schedule a little to accommodate the holiday weekend. And I never even thought about the caffeine effects until after my run and someone pointed it out.

agthorn

Okay, so I re-did the fitness test today, first thing in the AM. The polar is calculating my V02max at 50 and my resting heart rate at 58 (which checks out with the online calculators I've seen). It does have my maximum heart rate set at 190 so it's using the standard 220-age formula. I didn't check whether this can be manually changed or not.