Heart Rate Monitor - candid discussion

WallBilly
WallBilly Posts: 11 Member
in Fitness and Exercise
Almost every time someone posts a question here like "can I use an HRM to I estimate calories for doing X", be it figure skating, or CrossFit, or whatever . . . .

4 "experts" chime in and say "HRM is useless except for steady state cardio."

Well, thanks for that; what do you suggest?

If you scroll through the MFP exercise database or most other online tools, what you will find for calories expended for each exercise is simply an estimate for the average person of that weight doing something average. For example, if you put in 210 pounds and click many of the exercises, it is amazing how many times "762 calories" or "600 calories" pops up. Nobody measured anything, they just guess that jogging a 12 minute mile is kinda' like moderately riding an exercise bike or kinda' like traditional cross country skiing.

I've been wearing an HRM/strap for every activity for the last 3 months, and I believe that it gives me a pretty good indication of the effort that I put in, even if the calories are not exact. For example, I play ice hockey as a goaltender 2-3 times a week for 75 minutes. If you look up "Hockey, Ice" in MFP at 210 pounds, it tells you . . . . guess . . . . 762 calories for an hour. No indication of effort, how long you sit on the bench between shifts, whether you are a goalie or a skater, etc.

So, while it may not be accurate, the HRM gave me anywhere between 575 calories and 1150 calories for a 75 minute ice time, and everything in between. I can tell you that I almost died on the 1150 calorie day (no defense, lots of shots) and I barely needed a shower after the 575 calorie day (weak opposition, few shots, not much effort.) So, what good would it do me to put in the MFP 762 calories/hour? On a hard day, it's an underestimate; on an easy day, it is a serious overestimate, with almost twice as many calories granted than were actually expended.

The same thing happened for curling. In a 2 hour match, calorie burn according to the HRM varied between 600 and 1000 calories depending on effort. (Yeah, believe it or not, if you are sweeping right it is quite a good workout, like sprinting for 20 seconds followed by resting.) MFP gives 381 calories per hour with no adjustment for effort.

I've logged every single workout and every single calorie I have eaten for the last 4 months, and eaten back almost every single calorie that the heart rate monitor told me I burned. Assuming TDEE of 2550 + exercise, I should have lost 3.5 pounds in the last 2 months. The scale gives me 3 or 4 this week.

So, CICO seems to work pretty darned well, trusting the HRM even for activities that are not "steady state cardio", and eating back all the exercise calories (except for the deficit that I may be shooting for).

Now, I don't trust it always. I lift heavy, similar to Starting Strength. I don't believe anything it says on lifting, so I just give myself 200 calories an hour for that.

In summary, it is my opinion that using an HRM with some common sense is actually very useful for many "non-steady state" exercises. And it is a hell of a lot better than saying "look it up in the database and only eat back half."

Not to mention the activities that are not in the database.

$0.02

Replies

  • seska422
    seska422 Posts: 3,217 Member
    Most of what I've seen is don't trust the HRM for lifting, with which you agree.

    Everything to do with calories in and calories out is estimated. People need to experiment to find out what actually works for them and what does not. It sounds like you've done the legwork so you have a good grasp on your calorie burn so that you can eat back what you need to eat back.
  • blues4miles
    blues4miles Posts: 1,481 Member
    One thing to keep in mind with an HRM...

    It's not subtracting the normal calories your body would burn just by existing. So let's say I run for 40 minutes and it gives me 350 calories. 40 minutes is .67 hours. My BMR is ~1650. 1650 / 24 hours = 68.75 calories per hour, or 46 calories for those 40 minutes. So when I enter the calories burned into MFP, it would make sense to subtract the 46 from 350.

    Past that I'll say...we are all an experiment of one. We have to figure out what works for us. Whether or not the HRM is perfectly accurate is probably less important than if we are losing weight at the intended rate. I stopped using MFP numbers AND my HRM numbers for walking/running because I find them both to be inflated. My math was predicting I should have lost a certain amount of weight and I was losing less. First, I clamped down on my logging and weighing of my food. Then when the math still wasn't adding up, I started using more conservative numbers for my exercise. Now the math is back to working again. If you can eat back 1150 calories for a game of ice hockey and still lose weight at your desired rate, no reason to fix it if it ain't broke.

    I still love my HRM because for running it gives me a good indicator of whether I am pushing it that day, or sometimes it will be particularly high even if I am not going that fast which means it might be hot out or I might need to work on getting more sleep the night before. Or sometimes I will feel like quitting and look down and it's not very high and then I know it's all mental and in my head and I need to push myself a little more.
  • NorthCascades
    NorthCascades Posts: 10,968 Member
    I have my zones set up according to my LTHR. I wear my heart monitor for every workout that gets my heart rate elevated, so basically cycling and running, occasionally the elliptical or swimming in lakes in the summer. I use the recorded HR (time spent in each zone) as a way to judge the quality of a workout. Has nothing to do with calories but it's extremely useful.

    With that said, I measure my bike calories with a power meter (a device that measures the energy I put into the bike) and when I've done rides on other bikes, the calorie estimate from my HRM (Garmin Fenix 3) is always in the right ballpark.
  • MireyGal76
    MireyGal76 Posts: 7,334 Member
    I agree with you.

    Nothing is an exact science, so my approach is to lean towards a slight overestimate on calories consumed and a slight underestimate on calories burned. If I'm trying to lose weight, and I am, then I'm pretty confident that I'm doing ok. If I'm not losing weight, and I'm staying on track with my goal calories... then I drop my daily calorie estimate.

    It's all about tweaking the numbers so that they work for you.

    Great job in doing that!
  • Hornsby
    Hornsby Posts: 10,322 Member
    TDEE should include exercise. Not "+exercise" as you mentioned.

  • 3dogsrunning
    3dogsrunning Posts: 27,167 Member
    i don't disagree with your summary.

    In the past the information that HRMs are only good for steady state cardio was true. I am not an "expert" but I base this information off of people I know are pretty close to it.
    Newer models are using different technology that is supposedly more accurate for exercise outside steady state but I am not well versed as I mentioned. But a trusted friend has explained it ( @EvgeniZyntx ) to me.

    My objection always lies with people telling others they "need" a HRM to lose weigh or saying they are the most accurate. I also object to people complaining they aren't losing weight but insisting they are burning crazy amounts of calories because their HRM told them.


    As for your observation about many entries having the same amount of calories burned - MFP uses METs. It is likely that many exercise have the same MET. So it figures calories burned by multiplying your weight by the MET. So exercise with the same MET will give you same estimate.


    Using the MFP database is just like using a HRM, use common sense. For some exercises, it is fairly accurate. The more detailed an activity, like walking at a specific pace, the better of an estimate it is probably going to be. Like you noticed, entries like hockey with no indication of effort level is going to be less so.

    I lost weight using only MFP's entries. I've lost weight using my HRM numbers.

    In summary, use common sense an don't blindly trust any numbers. They are all estimates. Each method has its strengths and weaknesses.
  • 3dogsrunning
    3dogsrunning Posts: 27,167 Member
    This is a good read too

    http://www.myfitnesspal.com/blog/Azdak/view/estimating-calories-activity-databases-198041
  • WallBilly
    WallBilly Posts: 11 Member
    Hornsby wrote: »
    TDEE should include exercise. Not "+exercise" as you mentioned.

    Well, sure, if you want to average things out. The "T" does stand for "total" after all ;)

    I just assume 2550 for a normal recovery day, and add exercise on top of that if it's appropriate. Of course, there is a spreadsheet that figures out how much I should have lost . . .
  • stealthq
    stealthq Posts: 4,298 Member
    And for some of us an HRM doesn't work for steady state either because our heart rates fall outside the 'norm' and we don't have one that can be calibrated to correct for that.

    If I used mine to calculate calorie burns for distance running, I'd be believing I burn double what real world weight management experience shows is reality (and happens to agree with studies on the subject).
  • Azdak
    Azdak Posts: 8,281 Member
    There's always a difference between general guidelines and individual experience. In your case, you have found a pattern that works for you. However it could very well be that the "match" is just coincidence. That works great for you-which is the most important thing--but it might be useless for anyone else.

    For most people, our activity patterns are fairly consistent. By using an activity tracker and paying attention to the data, you should be able to get a sense of your TDEE. Even if the numbers are not precisely "accurate", the daily variations should reflect actual differences and you can match that with food intake and the scale to provide some guidance.

    I have a combo HRM and activity tracker (Polar V800, which is ridiculous overkill for me, but I like toys) which shows that my daily TDEE averages around 3100 kcal/day. That's probably an overestimate, but if I find that I keep my intake in the 1800-2000 calorie/day range (also a rough estimate), I will average between 1.5 and 2.0 lbs fat loss per week.

    Obviously, there is a difference whether the activity calories are spent walking the dog, doing yard work, leading training sessions, working out--or just walking around the house or the fitness center. However, based on 3 months of observation, it's close enough that I feel like I get acceptably useful feedback without having to spend a huge amount of time and effort counting and documenting.

    To do this, however, you have to be pretty consistent and you do have to do some analysis of the data and have the ability to draw conclusions from your observations. And it takes some time to figure it out. But until someone invents a $99 metabolic chamber for your house, it's still going to be a trial and error process.
  • ForeverIronman
    ForeverIronman Posts: 2 Member
    Maybe this is the elephant in the room but, I've a Timex Ironman HR watch which I'd love to use with Under Armour's apps; however, I've noticed that they're not even mentioned as a possibility. Is this a territorial despite between Timex and UA or, am I seriously behind the curve here?
  • ScubaSteve1962
    ScubaSteve1962 Posts: 609 Member
    blues4miles wrote: »
    One thing to keep in mind with an HRM...

    It's not subtracting the normal calories your body would burn just by existing. So let's say I run for 40 minutes and it gives me 350 calories. 40 minutes is .67 hours. My BMR is ~1650. 1650 / 24 hours = 68.75 calories per hour, or 46 calories for those 40 minutes. So when I enter the calories burned into MFP, it would make sense to subtract the 46 from 350.
    .

    This would depend on the which HRM your using. Mine will subtract them. IE: my calorie burn for the elliptical was 577 this morning total, but when I look at my actual calorie burn for the day, for training it was 478 which is then added to my bmr.

    I think where alot of people get confused is whether or not a person is trying to get their calorie burn, or see their actual effort for any giving activity. The same effort I started with to get my heart up to 80% is not the same effort that I need to get it there today 80%.

  • CincyNeid
    CincyNeid Posts: 1,249 Member
    I use my HRM as @NorthCascades uses their to measure myself and the intensity of my workout.

    I use a Mixture of Garmin Connect, Strava, and Training Peaks to measure myself and see how intense my workout was.

    The only time when I'm doing cardio, typically running or cycling, is when I'm climbing a hill or running up a hill and I want to keep myself out of the red zone so I don't fade to fast. And When I'm working on climbing faster I like to flirt with that line. So I can build my lungs & heart up and build me legs up.

    But I other than that my HRM is strictly for post workout numbers.
  • jacksonpt
    jacksonpt Posts: 10,413 Member
    I agree with the sentiment of the OP. Basically, all mainstream consumer-level methods of measuring calorie burn are crapshoots. Some may have less error for margin than others some of the time, but they all have a fairly high margin of error.

    They are, like everything else in this world of weight loss, weight gain, and exercise, an approximation. An estimate. How well HRMs work for you really comes down to how well that estimate works along side your approximation of your calorie intake.

    If one estimate is off by the same amount as the other, then the numbers will work out and you'll see, roughly, what you expect to see in terms of weight/progress. If they don't balance each other out, then in time we'll all see a "I'm doing everything right but not losing weight" post.

    It's rarely about everything being accurate, and more about everything playing nicely together.

Categories