Calculating BMR

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fteale
fteale Posts: 5,310 Member
in Fitness and Exercise
Can your calculate your BMR from your resting heart rate? If so, how?

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  • fteale
    fteale Posts: 5,310 Member
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    Also, how do you calculate your max heart rate?
  • MayhemModels
    MayhemModels Posts: 367 Member
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    calculate your max heart rate = 220 - your age
  • GaveUp
    GaveUp Posts: 308
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    I used this site, and I also have a HRM to keep me in the zone.

    http://www.freedieting.com/tools/target_heart_rate.htm
  • TrainingWithTonya
    TrainingWithTonya Posts: 1,741 Member
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    The BMR (Basal Metabolic Rate) is actually estimated based on your size. Heart rate doesn't play into it. The most accurate way to estimate it is through lab testing but it can be estimated with formulas. The easiest formula for BMR is 1 calorie per kilogram of body weight per hour. So, someone who is 100 kilograms (220 pounds) would multiply by 1 calorie and 24 hours to get their BMR of 2400 calories per day. To that, you then multiply by an activity factor to get your RMR (Resting Metabolic Rate), which is what MFP uses for Maintenance calories and subtracts your deficit from to give you a goal calorie level.

    The formula given above (220-age) is the easiest formula for max heart rate. The newest one, though, is 206.9 - (0.67 x age). They generally come pretty close to each other, though, like within 5 bpm, so whichever one you want to use is fine. Any of these calculations are simply estimates so there's not one that is 100% correct.
  • fteale
    fteale Posts: 5,310 Member
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    calculate your max heart rate = 220 - your age

    That is what my HRM calculates it on, but it isn't at all accurate for me. According to that equation my max heart rate should be 186, and it's far higher than that. I regularly get up to 182 just doing a normal training run, not even sprinting, which means my HRM is estimating that I am in training zone 5 all the time, which I am definitely not!
  • Aliciakay252
    Aliciakay252 Posts: 9
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    Hi! I am a Registered Dietitian and hold a Certificate in Training in Adult Weight Management.

    Mifflin St. Jeor equation has been shown to be the most accurate equation to calculate actual resting energy expenditure. The formula is as follows:

    Men: REE = 10W + 6.25H - 5A +5
    Women: REE = 10W +6.25H -5A -161

    W = weight in kg. (Take your weight in pounds divided by 2.2 to get it in kg)
    H = height in cm (take your height in inches multiplied by 2.54 to get it in cm)
    A = age in years

    Then there are various 'activity factors' that you multiply the REE by to get the TEE (Total energy expenditure). These activity factors vary depending on how active you are in your daily life.

    Hope this helps!
  • Swimgoddess
    Swimgoddess Posts: 711 Member
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    (The formula above gives me a BMR that is only 10 calories higher than MFP's calculator.)

    I prefer the Katch-McArdle method that takes into account your body composition. You do need to have a RELIABLE body fat measurement though.

    For example: I'm 156lbs

    Calipered BF: 19.8% (I use the same trainer each time, 7 point skinfold, yes my guy knows his stuff)
    Taped BF: 22% (http://www.healthcentral.com/cholesterol/home-body-fat-test-2774-143.html#accurate)
    Tanita BI scale: 34% (not very accurate, has only foot pads. Best kinds have hand grips & foot pads)

    I use my calipered amount, but that online measuring tape test isn't that far off.

    Formula:
    1.) Figure out your lean body mass. (100% - 19.8% = 80.2% of 156lbs = 125lbs)
    2.) Convert to metric. (125 / 2.2 = 56.8)
    3.) Plug n' play into Katch-McArdle formula. ((56.8 x 21.6) + 370)
    4.) Result is BMR. (1,597 calories/day)

    Reworking the formula with my taped BF result of 22% gives me 32 calories per day less. I still think this is a good option for people out there who don't readily have access to someone trained to take skinfold measurements with calipers.

    MFP says my BMR is 121 calories per day less than this which means they assume all 30 year old females on MFP are 27.5% body fat. I'll take the extra calories that the formula gives me since it literally knows what I'm made of.

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