THIS is why HRMs have limited use for tracking calories

froeschli

i use my hrm primarily as a guide to intensity i am running (exercising) at - because i tend to go faster than i ought to... calories burned are a neat number, but i'd have to more accurately track my food intake for it to matter anyhow.

composite

Exactly. I've worked out my TDEE by tracking my weight given a fixed intake level, and I've been maintaining the same weight for months now without tracking my exercise calories. If I wanted to lose more weight, I would simply cut calories by maybe 200/day without changing anything else. It all works well without using an HRM or the MFP exercise calorie guesstimator.

I have found that my Gamin 800 with HRM has been pretty accurate for me. I wanted to lose at 1lb a week and with eating back the calories burnt that it has said I have burnt I have consistently lost at roughly this amount. However I'm into endurance mountain biking and hope to race ultra endurance so the majority of my training certainly falls into the category of steady state cardio.

I'm currently reaching the end of an aerobic endurance phase and will be doing intervals next month. I'm curious how accurate my HRM will continue to be with that sort of work out.

nmfsc

Thank you for this information.

robert65ferguson

Thanks again Azdak for another gem. You certainly make a positive contribution for those of us who are lay people.

sheri02r

Great post!

MelodyandBarbells

Sorry if this is a dumb question but does this mean that the HRMs are best suited for steady cardio activities? Would they be relatively accurate for it?

Yes, those are the only conditions under which they should be considered reasonably accurate.

Now, that also assumes that they are: A) a quality model from a company that does their own research to develop their algorithms (e.g. Polar) and set up properly. To be most accurate, and HRM must be programmed with your actual HRmax and your actual VO2max. Those numbers are not always easily obtainable and some lower-level models (even Polars) do not allow you to manually input these variables. In that case, I don't know how you can make them more accurate.

For example, an HRM will set a default HRmax of 220-age (or close to that). We know that in the normal population, HRmax can vary 20-30 beats from that "220-age" number. If your HRM has a default HRmax of 180, for example, but your actual HRmax is 210, the HRM will substantially overestimate your calories burned--it thinks you are working much harder than you are.

Thanks! If anyone can confirm Polar uses 220 minus age to set HR max, then all we'd have to do is program a lower or higher age (the date of birth setting) to set our true HR max once measured. I'm still digging around trying to learn how best to determine this what my max HR is. I saw it in an old thread, I think. Any ideas?

MelodyandBarbells

I used this website from another post

http://www.briancalkins.com/HeartRate.htm

And it came up with 220 minus my age. I'll repeat the resting heart rate measurement a couple mornings after just waking up and before doing anything but so far we're awful darn close to the main stream assumption.

sijomial

I'm still digging around trying to learn how best to determine this what my max HR is. I saw it in an old thread, I think. Any ideas?

This is how I determined my max heart rate for cycling and calculating my heart rate zones for training - taken from http://www.bikeradar.com/fitness/article/heart-rate-monitor-training-for-cyclists-28838/

(Heed the warning about only doing it if you are fit and used to regular exercise!)

Many believe that you can calculate your maximum HR by using the formula of 220 minus your age. For some people this may be accurate, but for many it will be wildly out. I’m 54 years old so, using the formula, my max HR should be 166 (220-54). It’s actually 178, which is a big difference when training in very tight zones.

A much more accurate formula is 210 minus half your age, then subtract 5% of your body weight in pounds. Add four for a male and 0 for a female. The only way to get a truly accurate max HR figure is to get a physiological test at a sport science centre, such as Fletcher Sport Science, but you can get a reasonable estimate by doing your own max HR test. Only undertake this test if you are fit and exercise regularly, though.

Warm up thoroughly for at least 15 minutes. On a long, steady hill start off fairly briskly and increase your effort every minute. Do this seated for at least five minutes until you can’t go any faster. At this point get out of the saddle and sprint as hard as you can for 15 seconds. Stop and get off the bike and immediately check your HR reading. This is your max HR.

“Don’t forget that your max HR figure is sport specific,” says Fletcher. “This means that your maximum on a bike will invariably be much lower than it is when you're running because the bike is taking some of your weight.”

MelodyandBarbells

The max I ever hit in BodyCombat was 197 (mild dizziness, needed to catch my breath for a few seconds). Should I just use that? Mini enhanced formula posted above gives me less than 220 minus age. Otherwise I suppose I could try the bike thing, thanks! I just don't do much spinning or using the elliptical at the moment.

ElliInJapan

Thank you for posting this, it's very useful. One question regarding the chart though: if I read it correctly, I'd assume I could get a better estimate for my calories burnt during e.g. weight lifting by using a factor of 20-25% on my HRM's reading. Is that correct or does it vary so much that it's practically useless?

AntWrig

Thank you for posting this, it's very useful. One question regarding the chart though: if I read it correctly, I'd assume I could get a better estimate for my calories burnt during e.g. weight lifting by using a factor of 20-25% on my HRM's reading. Is that correct or does it vary so much that it's practically useless?

You shouldn't even worry about factoring in calories burn't during working out. First and foremost weight lifting shouldn't be used as a means of creating a deficit.

ElliInJapan

Thank you for posting this, it's very useful. One question regarding the chart though: if I read it correctly, I'd assume I could get a better estimate for my calories burnt during e.g. weight lifting by using a factor of 20-25% on my HRM's reading. Is that correct or does it vary so much that it's practically useless?

You shouldn't even worry about factoring in calories burn't during working out. First and foremost weight lifting shouldn't be used as a means of creating a deficit.

Absolutely, I know that. I'm just asking out of curiosity.

meeper123

Thanks!!

michellekicks

The max I ever hit in BodyCombat was 197 (mild dizziness, needed to catch my breath for a few seconds). Should I just use that? Mini enhanced formula posted above gives me less than 220 minus age. Otherwise I suppose I could try the bike thing, thanks! I just don't do much spinning or using the elliptical at the moment.

I use a max observed HR of 194bpm... all the formulas have me at about 183-184 for MHR, but I pushed it to 194 at the end of a 10km race where I PRd. I also know my LT sits high too - around 165bpm, which is about 85% of 194, so just about right. I can sustain 165-168bpm for over an hour, which if the formulas were accurate for me, would have me at well over 90% HRMax, which isn't likely.

Sarauk2sf

Tagging to point people towards. I bow to your geekiness on HRMs (said in a complementary and a good way) :happy:

peeaanuut

so from what I am understanding, why should I even bother to do weight lifting when I am trying to lose weight? I cant track the calories so unless I eat half of what I usually do on a lift day, I will come out above on my calories and the whole thing is wasted. So in other words, my hundred dollar purchase was a waste. Great.

jamielynas

strong post, thanks

shutupandlift13

Science. I like it.

Saving to link to all the "but my HRM told me I burned...." threads

:drinker:

chrismpalmer

so from what I am understanding, why should I even bother to do weight lifting when I am trying to lose weight? I cant track the calories so unless I eat half of what I usually do on a lift day, I will come out above on my calories and the whole thing is wasted. So in other words, my hundred dollar purchase was a waste. Great.

Not at all a waste. use your HRM when running. It's a useful piece of gear.

Weight training is important when trying to lose weight. If for no other reason than to maintain your muscle mass.It's extra work for sure, but hardly worthless.

linsey0689

Very interesting! Thanks for the post