# Training & Nutrition - Calories Burned by Heart Rate

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View Full Version : Calories Burned by Heart Rate

jcdebow
01-30-06, 12:49 PM
I've been trying to estimate calories in vs. calories out in order to lose fat. The 'in' has been straightforward, but the 'out' has been more difficult as it relates to riding. Many websites give you a rough estimate of calories burned riding at a certain speed for a certain time. Consensus seems to be that it is overstated.

Does anyone have info on calories burned as it relates to exercise intensity (time riding at a given % of max heart rate or LT) - anything more specific than the usual "Bicycling - vigorous effort" ?

Thanks

terrymorse
01-30-06, 01:07 PM
Well, you can make some educated guesses. But first you need to estimate your threshold power.

If you don't have a power meter, you can do an uphill time trial to estimate your threshold power. Ride up the hill at your threshold, then plug your stats into this calculator:

http://www.kreuzotter.de/english/espeed.htm

Now you have your threshold power. The only other thing you need is your resting heart rate.

Power starts at zero at your resting heart rate and increases linearly to your threshold power at your threshold heart rate. With that knowledge, it's easy to estimate power at any heart rate.

Power(HRx) = Power(THR) * (HRx - RHR) / (THR - RHR)

where:

HRx = current heart rate
THR = threshold heart rate
RHR = resting heart rate

To convert power in watts to calories of food needed to fuel that effort per hour, multiply the power above by 4.