Calculating Calories Burned

I've started exercising again and and trying to track my calories burned. I bought a heart rate monitor and used it for the first time this morning. The numbers it gave me are much higher than what apps that are based on time and speed calculate. For example, I rode my bike to work which took about 25 minutes at my slow pace. The heart rate monitor estimated 490 calories used and the app says 219. I'm curious as to which is more accurate. What are your opinions and what do you use?

I am sure there is a techy answer for this but I believe my HRM because it knows my height, weight (pre-programmed) and HR during exercise.

All of those are going to be approximate at best, and unless they have a place for you to enter your bodyweight, they're basically just guessing. Also, if you're getting your heart rate to 150% of resting for a minimum of 20 minutes, you're going to be burning calories at a higher rate for 4-8 hours after you stop.

~Boar

The only 100% way to know is go to a doctor and get hooked up to a test that is like a stress test. A good thing to do is find out what your BMI is and go from there. Everyone has a different percentage of fat in their body thus burn calories differently. Remember the more muscle you have the more calories you burn during the day.

The best thing to do to figure out how much weight you wanna loose is to figure out how many calories you burn on a normal day and then reduce your intake by 500. That should help you loose about 2 pounds a week.

I'd be more inclined to believe the heart rate monitor, especially if it has had you enter your height and weight.

Rather than worry about the exact number, I just use it as a benchmark. If I know my workout routine for 30 minutes burns X calories, then if I want a light day, I'll burn X/2 or 1.5X on a hard day, etc. Or note the difference of running at 6mph versus 6.5mph.

I'm about 3 weeks into using a HRM during my workouts and I was surprised how many calories it says I'm burning. I'm averaging around 700 for a 50min workout, which I didn't think was very accurate (it seemed high). But I had to enter my body weight, BMI, age, etc so who knows? I do mine through My Zone and the report it gives you on their website is pretty detailed and helpful. I still think that sounds like too high of an amount of calories burned, but I've never really tracked it before so I have nothing to refute it with.

I've been using a FitBit, I'm not sure how accurate it is, but it keeps track of all my steps during the day. I try to increase a little each day.

http://www.amazon.com/Fitbit-Wireless-Activity-Sleep-Tracker/dp/B0095PZHPE/ref=sr_1_1?ie=UTF8&qid=1358374349&sr=8-1&keywords=fitbit+ultra

If anyone runs you might wanna try Pear Sports it's on amazon. I bike so not really an advantage for me but it seems like a really great concept.

Short answer: Heart Rate monitors can over estimate the amount of calories burnt in a day. That being said most online guides (ie. Myfitnesspal, etc) also grossly over estimate the amount of calories burnt.

Longer Answer: Heart rate monitors measure how fast your heart is beating. They use an algorithm to estimate the amount of calories you burn; Height, weight and BMI can help make it more accurate but still over-estimation can range for 12%-33%. [sub]1[/sub]. Heart rate is a series of factors not limited to exertion. Stress, tempature and caffeine can all influence heart rate and have nothing to do with any sort of physical activity. Weight lifting can spike your heart rate, but doesn't follow the same formula that most monitors use.

They serve a purpose, but aren't the end all be all. A monitor with a chest strap that allows for the input of VO[sub]2[/sub] max will probably give you the most accurate reading. For running I use the following formula that I saw on Runner's World or some place similar....

Weight (in Pounds) x 0.63 x Distance (in Miles) = Calories burnt *******This only applies to actually jogging/running, walking has different co-efficents**********

Example: 235lbs x .063 = 148.05
148.05 x 3 = 444 Calories

YMMV

Breedy said:

A monitor with a chest strap that allows for the input of VO[sub]2[/sub] max will probably give you the most accurate reading.

Click to expand...

It was REALLY interesting to see the amount of calories I burned before and after I had my VO[sub]2[/sub] tested and then put into my HRM. This is a really good point!

Breedy said:

Short answer: Heart Rate monitors can over estimate the amount of calories burnt in a day. That being said most online guides (ie. Myfitnesspal, etc) also grossly over estimate the amount of calories burnt.

Longer Answer: Heart rate monitors measure how fast your heart is beating. They use an algorithm to estimate the amount of calories you burn; Height, weight and BMI can help make it more accurate but still over-estimation can range for 12%-33%. [sub]1[/sub]. Heart rate is a series of factors not limited to exertion. Stress, tempature and caffeine can all influence heart rate and have nothing to do with any sort of physical activity. Weight lifting can spike your heart rate, but doesn't follow the same formula that most monitors use.

They serve a purpose, but aren't the end all be all. A monitor with a chest strap that allows for the input of VO[sub]2[/sub] max will probably give you the most accurate reading. For running I use the following formula that I saw on Runner's World or some place similar....

Weight (in Pounds) x 0.63 x Distance (in Miles) = Calories burnt *******This only applies to actually jogging/running, walking has different co-efficents**********

Example: 235lbs x .063 = 148.05
148.05 x 3 = 444 Calories

YMMV

Click to expand...

so i use myfitnesspal but i use it to track more than keep an accurate count. it says I'm allowed 1450 a day in calories and i put food in by its bar code and when the bar code isnt there i try and over estimate the amount of calories but when it comes to putting in the calories burnt i go by what the CYBEX machine at the gym is telling me. It ask for my only my weight and i go by what it says and when i input it i leave some points off but not alot. should i be shaving more points off? If it says you burnt 480 should i be putting in 400, 380, less?

age too it ask for my age.

my fitness pal is pretty good too. Heart rate along with age and weight is the only way to get a "somewhat" accurate measurement. I use a Garmin watch with a heart rate monitor and I trust it but always assume it overestimates my calories burned. The better shape you are int he harder it will be able to tell as well.

Thanks for the info. I use my fitness pal to track my food intake and log the calories consumed that the hrm tells me. I try to make sure I'm not getting close to the estimated caloric limit that exercise adds an stay close to the pre-exercise calculation.

Myfitnesspal is good as a guide. I use it to and lost over 100lbs, took a little break over the holidays and I am around 235lbs now. To get a really good estimation you really need to get a digital scale and weigh out your food (a set of measuring cups come in handy too). Barcodes are fine but you need to make sure you know how many "servings" you eat. Another problem arise with something like meatloaf. Myfitnesspal has a wide range of descriptions...3 oz, 1/8 loaf, 1 slice. Which correspond to large variances in estimated calories.

I've found that Myfitnesspal also drastically over-estimates the amount of calories burned doing pretty much all activities. Generic machines and simple heart rate monitors do it to. Heart rate, in and of itself, has little direct relation to the amount of calories being spent. Peoples heart rates spike all the time for different reasons and to different degrees. Someone who is grossly out of shape could have a heart rate or 140 bpm simply walking at a brisk pace. On the other hand a skilled runner my cruise along with a heart rate of 120 bpm. Which one is burning more calories?

The simple answer is Physics. A calorie is a unit of energy, we burn energy to complete work. Work = Force x Distance. I gave a common formula for running in a previous post and admittedly I'm simplifying things.


ETA: When I go to the gym I and log "weightlifting" Myfitnesspal I usually drop 1/3 of my time off. Also, when it comes to machines I take the lower number of the 2 and drop 10%. On a purely personal level, I can do 30 minutes on an elliptical and burn more calories than 30 minutes of jogging/running, however after the elliptical I feel fine and after running I am sore and tired.

It really depends. They are all an estimate.

The Garmin stuff (at least up to the 310xt and 510) estimated about 1/3 too high. Thus, what the device says is 900kcal is actually 600kcal. This is not unique to Garmin, the apps you can get for your iPhone or Android device vastly overestimate.

We tend to underestimate calories in and overestimate calories out. Use your clothes or a scale.