Is my HRM causing me to lose less weight?

ashleyjohnstonn1
ashleyjohnstonn1 Posts: 359 Member
in Health and Weight Loss
Before I had my heart rate monitor (polar ft4) I was rarely working out and eating slightly better and I lost ten pounds quickly.

Now, I use my heart rate monitor and my food diary every single day for the past 4ish months and I haven't lost weight at all. Because I'm logging food so accurately I'm thinking that I must be overestimating my calories burned. However, in general, my HRM tells me I burn less than I usually see for most people.

For example, last week I went on stairmaster for an hour and it said I burned 500 calories, which I think is an overestimation, but other things like MFP say it is almost 700 calories and other people seem to burn way more calories (in group challenges etc) than I do doing the same activity.

I'm weighing everything I eat always (unless it is something prepackaged like a snack pack of almonds or something) and even though I'm not always eating healthy things I'm making sure that I do accurately log.

Typically I just use the basic math equation each week to see how much I should be losing based on my deficit. So I just take maintenance - cals eaten + exercise cals to get my deficit for the day and usually the numbers add up to over 3500 cals. Based on the math, I should be losing weight. The only thing I can think is that my HRM is inaccurate and I should log less calories burned for exercise. I also recently added in weight lifting - and that seems to be underestimated in my hrm burn. And I'm not "just gaining muscle so that's why i'm not losing" from lifting weights because my measurements from the past 4 months have stayed the same.

I'm just frustrated with my lack of results given all of the effort I'm putting in and I'd like some feedback as to what you think the problem could be.

Replies

  • pinkiezoom
    pinkiezoom Posts: 409 Member
    I too have the TF4 HRM, and i noticed that it was telling much lower calories burned than the machines at the gym, but I always use the HRM figures in my maths.
    I am no expert, but if you are trying to lose just a little bit of weight, from what i have read on other threads, it takes longer, although your time scale does seem very long. Sorry i couldnt be more help, is your diary open?
  • Sued0nim
    Sued0nim Posts: 17,456 Member
    What is your 'maintenance' then .. maybe that's wrong for you and you need to adjust it downwards

    I assume MFP has given you a calories to eat based on your required weight loss and then you are eating back whatever calories you burn in exercise - how about eating back less of them say 50%

    I got a Polar FT4 a couple of weeks ago and I'm going to watch carefully over the next month to see how much more I should be eating (I previously ate back 50% of MFP estimate) - but its for steady-state cardio work not weights

    If you are logging accurately as you say it should work, if it doesn't for 4 months I'd adjust it
  • ashleyjohnstonn1
    ashleyjohnstonn1 Posts: 359 Member
    edited October 2014
    I still have about 40 pounds to get to my "healthy weight" so there's a fair bit I still have to lose, as I am still in the overweight category.

    All of the maintenance calculators I use have me at around 2000 cals for maintenance right now so I'm going with 1800 because I want to underestimate a bit.

    I don't really focus on the cals mfp gives me I just use mfp to log but I have my own notebook where I'm just calculating my deficit every single day so sometimes I eat them back and sometimes I don't.

    There is something I need to adjust, I just don't know what yet. Although I pretty much eat a different number of calories every day so maybe it would be smart to go back to the mfp method and eat a strict number of cals every day and eat back 50% of exercise cals. I just hate that mfp has such a low calorie estimate for me when I see really successful people losing weight and eating more than 1200 calories. But I guess it wouldn't hurt to try to go back to the mfp method. Right now I'm kind of just making sure I log everything accurately and if I don't have the deficit I want for the day I just workout more the next day or go for a walk that night etc.
  • sijomial
    sijomial Posts: 19,809 Member
    People get a bit too hung up on HRM accuracy when really all you need is consistency! I used a basic HRM (Polar FT7) when I was losing weight. Simply took the numbers it gave me for eating back exercise calories but adjusted my calorie goal to get the desired weight loss results. I've since swicthed to a more sophistcated HRM (with customised VO2 max) for gym cardio and it gives about 10% lower calorie burns compared to the old one. When I use a Garmin HRM for cycling it's 10% lower again!
    In the end just work on using a consitent method and make calorie goal adjustments based on results - that also compensates for any food logging inaccuracy.
  • drosebud
    drosebud Posts: 277 Member
    edited October 2014
    The MFP approach has worked for me. My Polar FT4 shows my cardio burned cals at around 20-30% less than the MFP estimates, and I figure the Polar is more reliable. Based on this I normally cut back the non-cardio exercise that MFP calculates to around 75% of their figures. I eat back 50% of my exercise to err on the side of caution and also to give me a bit of wriggle room to go over on the days I don't exercise.

    Yes, it can be annoying that some can eat more, but it is pretty irrelevant for you: they may be heavier, taller, different age/gender, more active etc.

    For comparison I'm 5'3", 69kg, and have a base allowance of 1390 cals to target a half pound loss per week.
  • ashleyjohnstonn1
    ashleyjohnstonn1 Posts: 359 Member
    Thanks guys, I'm going to try to go back to the MFP method and eat back 50% of my exercise cals. Also, I'm going to log what my cal burn is as 10% lower than what it tells me. Better to underestimate than overestimate.

    Thank you for your input! I'm hoping that the change will help me meet my goals.
  • _whatsherface
    _whatsherface Posts: 1,235 Member
    My Polar FT4 is always reads lower than machines by like 200 calories. I go off my FT4 obviously. When I input my exercise into MFP it's pretty close to what my HRM said I burned which is a first lol. I almost always eat all of my exercise calories back. I try to save some though.
  • jacksonpt
    jacksonpt Posts: 10,413 Member
    HRMs, like all other calorie counters/calculators, are just estimating. There's no way to get around estimates, and there's no way to be truly accurate... not with calories going in or calories being burned. So a lot of this process, especially early on, is trial and error. Do something for a month, as consistently as you can, then evaluate the results and tweak your process accordingly. Rinse and repeat.

    Also, keep in mind that weight loss isn't linear. You'll have weeks where you lose a lot, and months where you lose nothing, despite "doing everything right." If you're confident in what you're doing, with your estimates and with the math, then trust the process. If, after a month, you aren't seeing results, tweak something (i.e. cut your intake by 10%).
  • bwogilvie
    bwogilvie Posts: 2,130 Member
    Studies show that HRM accuracy varies, especially for women. One study of the Polar F6 showed that, even calibrated with subjects' actual VO2max and HRmax, it overestimated energy expenditure by 27% (http://www.ncbi.nlm.nih.gov/pubmed/21178923). An earlier study showed that the Polar S410 overestimated energy expenditure in women by 12% (http://www.ncbi.nlm.nih.gov/pubmed/15292754). Another study found that the Polar S810i overestimated expenditure when exercising lightly but not moderately (http://www.jssm.org/vol9/n3/21/v9n3-21abst.php). The research seems to suggest that HRMs are less accurate for women than they are for men.

    The study by Keytel et al (http://www.ncbi.nlm.nih.gov/pubmed/15966347) that produced a widely-used formula found that it was reasonably accurate for groups when VO2max had been measured, but less accurate without measurement of VO2max - in the latter case, over 26% of the variance in energy expenditure was not explained by their equation, which uses heart rate, gender, age, and weight to estimate calories consumed.

    The takeaway: if your heart rate is higher than the "typical" person of your age, weight, and gender, the HRM will overestimate your calorie burn. Try logging only 80% of HRM-estimated calories and see what happens.

    Also, HRM energy estimations are designed to be accurate for moderate to intense, steady-state cardio, such as running, cycling, cross-country skiing, etc. They are less accurate for variable-speed cardio, and practically useless for weight training, where the correlation between your heart rate and your energy expenditure is much weaker than with steady-state cardio.
  • pcaakes
    pcaakes Posts: 33 Member
    I calculate cals burned however equipment is set to calculate calories burned based on a 150# person. Below is a breakdown of High Intensity Exercise (expl Jogging, stair machine racquetball vigorous swimming)
    Wt Cal Burned
    100-120 7 cal /min
    121-140 9 cal / min
    141-160 10 cal / min
    161-180 11 cal / min
    181-200 12 cal /min
    201-220 13 cal / min
    221-240 14 cal / min
    241-260 15 cal / min
    261-280 16 cal / min
    281-300 17 cal / min
    301-320 18 cal / min
    321-340 19 cal / min
    341-360 20 cal / min
    361-380 20 cal / min
    381-400 21 cal / min
    Over 400 22 cal / min
  • Kettle_Belle14
    Kettle_Belle14 Posts: 246 Member
    bwogilvie wrote: »
    Studies show that HRM accuracy varies, especially for women. One study of the Polar F6 showed that, even calibrated with subjects' actual VO2max and HRmax, it overestimated energy expenditure by 27% (http://www.ncbi.nlm.nih.gov/pubmed/21178923). An earlier study showed that the Polar S410 overestimated energy expenditure in women by 12% (http://www.ncbi.nlm.nih.gov/pubmed/15292754). Another study found that the Polar S810i overestimated expenditure when exercising lightly but not moderately (http://www.jssm.org/vol9/n3/21/v9n3-21abst.php). The research seems to suggest that HRMs are less accurate for women than they are for men.

    The study by Keytel et al (http://www.ncbi.nlm.nih.gov/pubmed/15966347) that produced a widely-used formula found that it was reasonably accurate for groups when VO2max had been measured, but less accurate without measurement of VO2max - in the latter case, over 26% of the variance in energy expenditure was not explained by their equation, which uses heart rate, gender, age, and weight to estimate calories consumed.

    The takeaway: if your heart rate is higher than the "typical" person of your age, weight, and gender, the HRM will overestimate your calorie burn. Try logging only 80% of HRM-estimated calories and see what happens.

    Also, HRM energy estimations are designed to be accurate for moderate to intense, steady-state cardio, such as running, cycling, cross-country skiing, etc. They are less accurate for variable-speed cardio, and practically useless for weight training, where the correlation between your heart rate and your energy expenditure is much weaker than with steady-state cardio.

    Wow, I find this very interesting. I'm relying on my HRM (Polar FT4) for my calorie burn as well, and I, too, am having trouble losing weight. Thanks for this, it's helped me a ton!
  • h7463
    h7463 Posts: 626 Member
    edited October 2014
    Hi there!
    No, it probably isn't the HRM.... I've noticed the same thing here... Before I used one, I made notes about my calorie intake, but worked out like a maniac, not eating much, if anything, back... Now that I have a better guess at my actual calories burnt, I'm eating more food to really meet my goal net calories, resulting in slower progress. But it's still progress, so I'm not complaining. Another plus, I'm recovering faster, too, because I get more food into my sore muscles.

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