Yes, another TDEE question ...

shortie_sarah
shortie_sarah Posts: 177 Member
in Health and Weight Loss
I was wondering if you could use a HRM to determine your TDEE? All of the calculators are giving me different results and I don't want to assume I'm using the correct one and it be all wrong for me. Would using a HRM for a full 24 hour period and taking my average HR to figure out the calories burned then adding that to my BMR give me an accurate result? If this is all wrong thinking, I won't take any offense to it, it was just an idea that I had. MFP has me set at 1200 calories a day which seems like, from all of the posts by experienced MFP members, is too low. I am not a patient person and I want to see results quickly, BUT I don't want to do this the wrong way, either. I know I may have to suck it up and just give it time. I do know that this is a lifestyle change for me. Not a diet or a fad. This IS how it's going to be for now with me and I want to do it the correct way. If anyone could please help me out I would really appreciate it!

Here are my stats in case they are needed:

Age: 24
SW - 167
CW - 157
GW - 120-115
HT - 5'1


ETA: I am a stay at home mom so I mostly sedentary, however, I do house work and have 3 young kids to take care of. I am also starting a 30 day challenge next week that will have me working out 5-6 times a week

Replies

  • Calliope610
    Calliope610 Posts: 3,783 Member
    Take the average of all the different TDEE results. A TDEE variance of +/- 5% isn't going to make a huge difference in your results.
  • djeffreys10
    djeffreys10 Posts: 2,312 Member
    No. HRM is generally only good for steady state cardio.
  • purdynerdybirdy
    purdynerdybirdy Posts: 20 Member
    HRM are not meant for all day use, just for exercise. If you want a good approximation of your TDEE, try getting something like FitBit or BodyMedia.
  • DonnaRe2012
    DonnaRe2012 Posts: 298 Member
    Take the average of all the different TDEE results. A TDEE variance of +/- 5% isn't going to make a huge difference in your results.


    ^^^^^^^^ This
  • heybales
    heybales Posts: 18,842 Member
    In addition to the correct comments on HRM, your other thought you could add it's results to your BMR for total burn is mistaken thought on what HRM is estimating.

    It actually includes what you would have burned anyway for RMR you might say. RMR is slightly higher than BMR.

    Database tables, machines, and HRM's, and most calculators, provide Gross calorie estimates, not Net calories burned as you might be thinking.
    So it's total calories burned during that time, not just the calories burned extra, because nothing would know that. Well, ok, Polar has enough info it could, but it doesn't.
  • shortie_sarah
    shortie_sarah Posts: 177 Member
    so, what is the difference between a fitbit zip and a HRM?... I know an HRM measures your beats, and fitbit measures calories, but couldn't you just plug the result from your HRM into a calculator and get the same results?... Sorry for the questions, I just really want to understand this completely. Thanks!
  • heybales
    heybales Posts: 18,842 Member
    so, what is the difference between a fitbit zip and a HRM?... I know an HRM measures your beats, and fitbit measures calories, but couldn't you just plug the result from your HRM into a calculator and get the same results?... Sorry for the questions, I just really want to understand this completely. Thanks!

    First - neither measures your calories burned. That is estimated from formulas.

    As far as calories is concerned, there is a loose correlation between HR and calories burned if you have a bunch of personal stats correct, you can be 70% accurate on calorie burns.
    Yes you can take your avgHR during a workout and plug in to same formula's the HRM uses and get an estimate. But those formulas are only for aerobic exercise, not below exercise, not anaerobic, and not steady-state where HR is moving all over the place.

    Movement devices base it on also highly accurate movement and calorie burn, if movement matches what can be highly accurate.

    Walking up to 4mph and jogging from 4.2 to 6.3 mph level is very highly accurate in formulas against measured calories burned, more than HRM's even.

    So they try to translate movement with your weight to calories burned. Again, depending on the daily activity and exercise, can be decent, or more accurate.

    Sometimes not.
    http://well.blogs.nytimes.com/2013/06/12/how-accurate-are-fitness-monitors/
  • shortie_sarah
    shortie_sarah Posts: 177 Member
    ok, thanks for clearing that up for me
  • shortie_sarah
    shortie_sarah Posts: 177 Member
    I'm finding that my average TDEE is 1,800
  • jzammetti
    jzammetti Posts: 1,956 Member
    I have to be the one who is different... I have tried several ways to estimate my TDEE and my HRM is accurate for me.:noway:

    I have a Polar FT4 and my user manual suggests that I wear it for three 24-hour periods to estimate my TDEE (they don't use that word...). Everyone on the forums acted like I was sacrificing a newborn when I said I used those numbers for my TDEE.

    I emailed to company to see what they would say about accuracy for activity other than steady state cardio - they replied that the monitor will be accurate for any level of activity so long as I have a heart beat (again, not those exact words).

    So, I had no idea if the HRM is accurate when not in steady state cardio or not. Forum people tell me no, Polar says yes. I go with the manufacturer's response. My HRM estimates me at 2350 calories per day (an average of three days - one workout, two not workout). When I changed my calories based on those numbers, I got results. (this involved upping my calories by over 300 per day to get to a 10% deficit from HRM numbers).

    All the online calculators say I should be eating around 1700 a day (presuming a 10% deficit). I ate that for a long time (over a year) and it worked, but then I plateaued (for 6 months) so in desperation I changed my calories according to my HRM numbers. Guess what? It worked. Started losing again.

    So, I don't understand all the science talk that gets put on the forums really, but I do understand results. Using my HRM estimates gives me results so I don't doubt it.
  • shortie_sarah
    shortie_sarah Posts: 177 Member
    I have to be the one who is different... I have tried several ways to estimate my TDEE and my HRM is accurate for me.:noway:

    I have a Polar FT4 and my user manual suggests that I wear it for three 24-hour periods to estimate my TDEE (they don't use that word...). Everyone on the forums acted like I was sacrificing a newborn when I said I used those numbers for my TDEE.

    I emailed to company to see what they would say about accuracy for activity other than steady state cardio - they replied that the monitor will be accurate for any level of activity so long as I have a heart beat (again, not those exact words).

    So, I had no idea if the HRM is accurate when not in steady state cardio or not. Forum people tell me no, Polar says yes. I go with the manufacturer's response. My HRM estimates me at 2350 calories per day (an average of three days - one workout, two not workout). When I changed my calories based on those numbers, I got results. (this involved upping my calories by over 300 per day to get to a 10% deficit from HRM numbers).

    All the online calculators say I should be eating around 1700 a day (presuming a 10% deficit). I ate that for a long time (over a year) and it worked, but then I plateaued (for 6 months) so in desperation I changed my calories according to my HRM numbers. Guess what? It worked. Started losing again.

    So, I don't understand all the science talk that gets put on the forums really, but I do understand results. Using my HRM estimates gives me results so I don't doubt it.

    Thanks for letting me your experience. I never thought to look to my manual! :embarassed: I may give it a go just to see what I come up with.

    Also, I am looking to lose about 42 more pounds so what percentage should I subtract for my deficit once I get my TDEE worked out?
  • jzammetti
    jzammetti Posts: 1,956 Member
    I have to be the one who is different... I have tried several ways to estimate my TDEE and my HRM is accurate for me.:noway:

    I have a Polar FT4 and my user manual suggests that I wear it for three 24-hour periods to estimate my TDEE (they don't use that word...). Everyone on the forums acted like I was sacrificing a newborn when I said I used those numbers for my TDEE.

    I emailed to company to see what they would say about accuracy for activity other than steady state cardio - they replied that the monitor will be accurate for any level of activity so long as I have a heart beat (again, not those exact words).

    So, I had no idea if the HRM is accurate when not in steady state cardio or not. Forum people tell me no, Polar says yes. I go with the manufacturer's response. My HRM estimates me at 2350 calories per day (an average of three days - one workout, two not workout). When I changed my calories based on those numbers, I got results. (this involved upping my calories by over 300 per day to get to a 10% deficit from HRM numbers).

    All the online calculators say I should be eating around 1700 a day (presuming a 10% deficit). I ate that for a long time (over a year) and it worked, but then I plateaued (for 6 months) so in desperation I changed my calories according to my HRM numbers. Guess what? It worked. Started losing again.

    So, I don't understand all the science talk that gets put on the forums really, but I do understand results. Using my HRM estimates gives me results so I don't doubt it.

    Thanks for letting me your experience. I never thought to look to my manual! :embarassed: I may give it a go just to see what I come up with.

    Also, I am looking to lose about 42 more pounds so what percentage should I subtract for my deficit once I get my TDEE worked out?

    Less than 50 to lose, go with a 15% cut. When you get to 20/25 to lose, drop to a 10% cut. It goes slower whether we like it or not and as you get closer to your goal. make sure to take measurements and track those too - sometimes the scale lies!! :)
  • heybales
    heybales Posts: 18,842 Member
    Man, I read all through the printed and online manual for my FT7 and RS300X. Never a comment about wearing for 3 days. I'd love to see that reference.

    Here is a Polar funded study with the comments regarding when the formula's do and don't apply.

    http://www.braydenwm.com/cal_vs_hr_ref_paper.pdf

    "Acknowledgments
    We thank all of the participants for their cooperation. This study was funded by Polar
    Electro Oy, Kempele, Finland, the Medical Research Council of South Africa, and the
    Nellie Atkinson and Harry Crossley Staff Research Funds of the University of Cape
    Town."

    "Introduction
    During moderate physical activity, there is a linear relationship between heart
    rate and oxygen consumption. This heart rate--oxygen consumption relationship
    is subject to both intra- and inter-individual variability. Heart rate may be partially
    dissociated from energy expenditure by factors such as emotion, posture and
    environmental conditions (Hebestreit & Bar-Or, 1998). The relationship between
    heart rate and energy expenditure is linear only within a relatively narrow range
    of approximately 90-150 beats x [min.sup.-1] (the so-called "flex heart rate") during physical activity (Ceesay et al., 1989; Rennie, Hennings, Mitchell, &
    Wareham, 2001; Spurr et al., 1988). During light activity or inactivity, there is
    almost no slope to the relationship between heart rate and energy expenditure,
    and for the purpose of measuring energy expenditure from heart rate it is
    assumed that energy expenditure is equal to resting energy expenditure (Rennie
    et al., 2001). A non-linear, discontinuous function has been found to be more
    accurate than a linear relationship in predicting physical activity energy
    expenditure from heart rate (Li, Deurenberg, & Hautvast, 1993)."

    So at best, what Polar HRM may be doing, is if your HR is under that flex HR value, they know your BMR by your stats and can estimate RMR from that, and may just use your RMR for that time.

    But the studies referenced in this study and more recent ones have proved out that below exercise level, activity devices like FitBit and such have better chance of accuracy.

    So that's why everyone comments HRM's are no good at calorie estimates for non-aerobic exercise range activity. Anaerobic is inflated, and generally below exercise is inflated.

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