Equation Used for calculating calories burnt?

bathedinshadow

Hello....

I posted this question in a different thread but I think it may have gotten lost since it wasn't really in line with the topic. So I thought I'd post it separately.

Yesterday I had a sort of lower impact exercise. I hiked up a mountain for just over 2 hours. But I really wasn't feeling tired at all and my heart rate was pretty low. Given that i wasn't on my own, I couldn't just up the pace. Anyway I burnt almost 900 calories but because it took me so long to burn that much I really wanted to deduct from that number how many calories I would have burnt if I were just sitting around the house. So I was going to wear my HRM for a few hours to get an idea of how many calories that would be. As it turns out, my HRM doesn't show calories burned when my heart rate is that low. I don't know how high it needs to be in order to register, but I have a very low resting heart rate at 49-51 bpm.


SO... I was wondering if anybody else has this problem? I have the Timex Ironman. It works great otherwise. Or perhaps does anybody know what the equation is that these watches use? I could just wear it for my average heart rate and figure it out myself.

Thanks. :flowerforyou:

bathedinshadow

Hello....

I posted this question in a different thread but I think it may have gotten lost since it wasn't really in line with the topic. So I thought I'd post it separately.

Yesterday I had a sort of lower impact exercise. I hiked up a mountain for just over 2 hours. But I really wasn't feeling tired at all and my heart rate was pretty low. Given that i wasn't on my own, I couldn't just up the pace. Anyway I burnt almost 900 calories but because it took me so long to burn that much I really wanted to deduct from that number how many calories I would have burnt if I were just sitting around the house. So I was going to wear my HRM for a few hours to get an idea of how many calories that would be. As it turns out, my HRM doesn't show calories burned when my heart rate is that low. I don't know how high it needs to be in order to register, but I have a very low resting heart rate at 49-51 bpm.


SO... I was wondering if anybody else has this problem? I have the Timex Ironman. It works great otherwise. Or perhaps does anybody know what the equation is that these watches use? I could just wear it for my average heart rate and figure it out myself.

Thanks. :flowerforyou:

dclarsh

Try taking the maintenance calories at the sedentary level and dividing it by 24. That should give you a rough estimate of what you burn in an hour just sitting around breathing.

bathedinshadow

Yeah I thought of that... I was just looking for a more accurate estimate.

Thanks though!

pixiestick

the have you thought of wearing your HRM during a normal part of the day and then dividing those cals by the number of hours you'd been wearing the machine. That would give you a little bit more accurate of a read than the first option. I have to say, though, dclarsh's suggestion (while not 100% accurate) would give you a great estimate without a lot of extra trouble.

pettmybunny

Here is a website link to the formula used by the Timex Ironman HRM. I did see your post when I was on lunch, but I was at work, and couldn't access the information at the time.

http://www.thedailyplate.com/forum/viewtopic.php?p=111941&sid=78802b2b48abcd0033e10a7e35554045

Here's the actual formula from that post...

(1+0.0276*(HR-100))*(3.5+0.0887*(W-40))*T

HR = Average Heart Rate for workout
W = Weight in KG
T = Time of workout in minutes

My DH is a math minor, and did all the hard calculations for me When we did it, it came right out to what the monitor said so the monitor is working... But then we did it with my resting heart rate, and it says that I burn over 4000 calories in a day, just by doing nothing. I think that there's something a bit screwy with their calculation. I now mainly use my monitor just to make sure my heart rate is where it needs to be. I use the calories burned from the machines and this site when adding in my exercise, instead of the calories my HRM says I burned.

bathedinshadow

the have you thought of wearing your HRM during a normal part of the day and then dividing those cals by the number of hours you'd been wearing the machine. That would give you a little bit more accurate of a read than the first option. I have to say, though, dclarsh's suggestion (while not 100% accurate) would give you a great estimate without a lot of extra trouble.

Yes, but as I mentioned in my question (maybe not clearly though) my HRM doesn't count calories when my heart rate is low. I'm trying to be as accurate as possible, so I am trying to avoid the other option if I can find a way.

bathedinshadow

Here is a website link to the formula used by the Timex Ironman HRM. I did see your post when I was on lunch, but I was at work, and couldn't access the information at the time.

http://www.thedailyplate.com/forum/viewtopic.php?p=111941&sid=78802b2b48abcd0033e10a7e35554045

Here's the actual formula from that post...

(1+0.0276*(HR-100))*(3.5+0.0887*(W-40))*T

HR = Average Heart Rate for workout
W = Weight in KG
T = Time of workout in minutes

My DH is a math minor, and did all the hard calculations for me When we did it, it came right out to what the monitor said so the monitor is working... But then we did it with my resting heart rate, and it says that I burn over 4000 calories in a day, just by doing nothing. I think that there's something a bit screwy with their calculation. I now mainly use my monitor just to make sure my heart rate is where it needs to be. I use the calories burned from the machines and this site when adding in my exercise, instead of the calories my HRM says I burned.

Oh thanks! I'll give it a shot and see what kind of number I come up with. I'm pretty sure when I workout that my HRM is doing an accurate measure of calories burnt... it's just once my heart rate drops below something like 75 it stops counting calories burnt for some reason. I wore it for 3 hours just walking around the other day and it said I didn't burn any calories. I have a pretty slow hear rate at 50 bpm so it would never be resting at 75. In fact get me really relaxed and it will drop to 47.

Thanks for the replies!

bathedinshadow

Awesome... I would say that is probably right. The equation is written out a little strange (no fault of yours of course), but it seems right.

ce_fit

I to have the timex Ironman but am starting to question the accuracy of the calories burnt. When you set up the basic information it ask's the following, Age, weight and max heart rate. It does not ask your sex or height.

So without those to factors included in the calculation is it possible for the results on calories burned be accurate.

bathedinshadow

Hmmm that's a good question. I don't know. I haven't used the other HRM's so I don't know what they ask for even. Do they ask for that information? I went with the Timex because it got great reviews and it's like half the size! Not to mention the girls versions of the other HRM's were all like powder colors. Bleh.

But yeah, I'd be curious to know myself!

pixiestick

I have the polar F6 and it asked for height and sex in addition to weight, age, and max heart rate.

I've heard good things about the Timex Ironman though; do you know someone who has an HRM with the additional user/profile information? you could work out a few times using that and see how the two compare.

:flowerforyou:

SHBoss1673

you should probably ask the timex people if it deducts your daily calories from the equation. Polar doesn't so you need to be aware that in long workouts, 80 to 120 calories per hour are from your resting metabolism. But each company does it different, so if you send them an email, they will let you know. It sounds, though, as if the ironman already deducts them. Which is good in some ways, but bad if you just want to know your daily maintenance.

pettmybunny

Hmmm that's a good question. I don't know. I haven't used the other HRM's so I don't know what they ask for even. Do they ask for that information? I went with the Timex because it got great reviews and it's like half the size! Not to mention the girls versions of the other HRM's were all like powder colors. Bleh.

But yeah, I'd be curious to know myself!

Yeah, that's why DH bought me mine, when he got it for my birthday. All I know is I get wild crazy high numbers... Like burning 700 calories for half an hour of lifting weights. I know I'm pushing hard and I don't rest between sets (I alternate machines on different muscle groups), but I can't believe I'm burning that much!

Like I said earlier, my HRM reads consistently 2 to 3 times higher than machines and websites for calories burned. If I'm on a machine, I use those numbers, if I'm out doing something else, I just divide what my HRM has by 3. I know it's got to be closer to reality that way.

KatWood

Hi everyone!
I have a timex too and I love it. I have compared it to several exercise machines and it matched all of them in terms of heart rate. In terms of calories burned, it matches equipment that takes weight into account, but is high compared to those who don't. I think its because I am heavier than the average gal.

bathedinshadow

Hmmm that's a good question. I don't know. I haven't used the other HRM's so I don't know what they ask for even. Do they ask for that information? I went with the Timex because it got great reviews and it's like half the size! Not to mention the girls versions of the other HRM's were all like powder colors. Bleh.

But yeah, I'd be curious to know myself!

Yeah, that's why DH bought me mine, when he got it for my birthday. All I know is I get wild crazy high numbers... Like burning 700 calories for half an hour of lifting weights. I know I'm pushing hard and I don't rest between sets (I alternate machines on different muscle groups), but I can't believe I'm burning that much!

Like I said earlier, my HRM reads consistently 2 to 3 times higher than machines and websites for calories burned. If I'm on a machine, I use those numbers, if I'm out doing something else, I just divide what my HRM has by 3. I know it's got to be closer to reality that way.

You have the Ironman? There are a few different versions of it, but mine definitely doesn't show those kinds of numbers! What is your average heart rate during your workouts? And if you don't mind me asking, how much do you weigh? I burn about 700 in an hour doing strength training.... with my trainer. So it's very intense. I only ask because that does sound high and maybe something is wrong with yours?

bathedinshadow

you should probably ask the timex people if it deducts your daily calories from the equation. Polar doesn't so you need to be aware that in long workouts, 80 to 120 calories per hour are from your resting metabolism. But each company does it different, so if you send them an email, they will let you know. It sounds, though, as if the ironman already deducts them. Which is good in some ways, but bad if you just want to know your daily maintenance.

You know I don't know. haha. This is funny, I'm usually FULL of questions - pestering people in order to get every last detail down and now... two questions in a row that I haven't thought of. Yes that would change my use of the equation to figure out my daily maintenance. I may have to contact Polar and see what equation they use if Timex factors it in already. Do you think not putting in my height and sex would really change the calorie burnt number?

pettmybunny

Yeah, that's why DH bought me mine, when he got it for my birthday. All I know is I get wild crazy high numbers... Like burning 700 calories for half an hour of lifting weights. I know I'm pushing hard and I don't rest between sets (I alternate machines on different muscle groups), but I can't believe I'm burning that much!

Like I said earlier, my HRM reads consistently 2 to 3 times higher than machines and websites for calories burned. If I'm on a machine, I use those numbers, if I'm out doing something else, I just divide what my HRM has by 3. I know it's got to be closer to reality that way.

You have the Ironman? There are a few different versions of it, but mine definitely doesn't show those kinds of numbers! What is your average heart rate during your workouts? And if you don't mind me asking, how much do you weigh? I burn about 700 in an hour doing strength training.... with my trainer. So it's very intense. I only ask because that does sound high and maybe something is wrong with yours?

Yup, I've got the Ironman... Average heart rate is anywhere from 168 to 176, for cardio (max is generally in the 180's somewhere, once in a while low 190's). When doing the strength training, my average heart rate is in the 140's (max is around 185). I should add that I don't rest between sets, I go back and forth between machines that work different muscle groups (I read somewhere today, that these are called supersets?), so that may have something to do with it too... My resting HR is upper 70's, low 80's, I weigh about 185 right now.

bathedinshadow

Yeah, that's why DH bought me mine, when he got it for my birthday. All I know is I get wild crazy high numbers... Like burning 700 calories for half an hour of lifting weights. I know I'm pushing hard and I don't rest between sets (I alternate machines on different muscle groups), but I can't believe I'm burning that much!

Like I said earlier, my HRM reads consistently 2 to 3 times higher than machines and websites for calories burned. If I'm on a machine, I use those numbers, if I'm out doing something else, I just divide what my HRM has by 3. I know it's got to be closer to reality that way.

You have the Ironman? There are a few different versions of it, but mine definitely doesn't show those kinds of numbers! What is your average heart rate during your workouts? And if you don't mind me asking, how much do you weigh? I burn about 700 in an hour doing strength training.... with my trainer. So it's very intense. I only ask because that does sound high and maybe something is wrong with yours?

Yup, I've got the Ironman... Average heart rate is anywhere from 168 to 176, for cardio (max is generally in the 180's somewhere, once in a while low 190's). When doing the strength training, my average heart rate is in the 140's (max is around 185). I should add that I don't rest between sets, I go back and forth between machines that work different muscle groups (I read somewhere today, that these are called supersets?), so that may have something to do with it too... My resting HR is upper 70's, low 80's, I weigh about 185 right now.

Well you should be burning more calories than me then. My average heart rate is similar. But given that you are a little older than me and are working with more weight, you should be burning more. I don't know about twice as much, but definitely more. So here is what did, I used the equation that you were kind enough to dig up for me and plugged some numbers in.

If you were to do cardio for 30 minutes with an average heart rate of 170 at your weight you should be seeing a 651 calorie burn (according to the equation).

If you were to do weight training for 30 minutes with an average heart rate of 145 at your weight you should be seeing a 498 calorie burn (according to the equation).

I verified this by putting in my numbers from my workout today. I did the equation myself and then looked to see what my HRM said and it was only a 5 calorie difference which could have been attributed to the fact that I rounded my weight when I converted to KG.

SO... I would say yours is a bit off and that it's not calculating according to the equation. The equation doesn't factor in max heart rate. I don't know if that makes a difference. I too do a similar kind of weight training. I don't take rests and just jump from one thing to the next for an hour. I pretty intense but don't you feel good afterwards!

osmium

I use a Polar F6 and I just compared my last run values to the values I'd get from your equation. They are different by a factor of 2! I just don't understand how they can be so different.

My Polar F6 numbers - 50mins 495cals avg HR 151bpm

The Equation gives me 957cals.

T=50
W=90
HR=151

I am 90kg.

There must be something wrong somewhere.

bathedinshadow

I use a Polar F6 and I just compared my last run values to the values I'd get from your equation. They are different by a factor of 2! I just don't understand how they can be so different.

My Polar F6 numbers - 50mins 495cals avg HR 151bpm

The Equation gives me 957cals.

T=50
W=90
HR=151

I am 90kg.

There must be something wrong somewhere.

Yes, I just put in your figures and got 955.213. That does sound high. I'm going to have to track down the equation that the Polar F6 uses and see what comes up.