When you walk or run on a treadmill, you burn calories from fat and carbohydrates. The percentage of calories you burn from fat depends on the intensity of the exercise. More intense exercises raise your heart rate higher and demand a higher proportion of calories from fast-burning carbohydrates and fewer from slow-burning fat. However, this does not mean that low-intensity exercises will help you burn fat faster. High-intensity exercises, such as running on the treadmill instead of walking, burn more total calories, including calories from fat.
Finding Your Maximum Heart Rate
Step 1
Walk at a comfortable pace on the treadmill until your heart rate reaches 100 to 120 beats per minute.
Step 2
Run 1/4 of a mile, beginning with an easy jog and increasing your speed every 1/16 mile until you are running at your fastest speed.
Step 3
Write down the highest heart rate recorded by your heart monitor.
Step 4
Walk slowly for two to five minutes, then run another 1/4 mile.
Step 5
Select the highest heart rate you attained between the two runs. This is your maximum heart rate.
Calculating Fat Burned
Step 1
Note your average speed and your heart rate the next time you exercise on the treadmill.
Step 2
Divide your heart rate by your maximum heart rate. Multiply this number by 100 to calculate the percentage of your maximum heart rate you reached while exercising.
Step 3
Determine the metabolic equivalent level appropriate to your exercise by comparing your walking or running speed to those listed on a MET chart. METs compare your energy expenditure with the amount of energy you expend when at rest. For example, walking at three miles per hour gives you a MET level of 3.5, which means that you are expending 3.5 times more energy while walking than when you are resting.
Step 4
Substitute the METs and your weight in kilograms into the formula for energy expenditure per minute: Energy expenditure = 0.0175 x MET x weight (in kilograms).
Step 5
Multiply the energy expenditure per minute by the number of minutes you spent exercising. The answer is the total number of calories you burned.
Step 6
Multiply the number of calories you burned by the percentage of calories you burned from fat. According to Heart Zones, this percentage is relative to the percent of your maximum heart rate that you attained while exercising. For example, if you attained 50 to 60 percent of your maximum heart rate, 70 to 85 percent of the calories you burned were from fat. This means that if you burned 100 calories, 70 or more of those calories were from fat.
Step 7
Subtract the calories from fat from 3,500, which, according to MayoClinic.com, is approximately the number of calories it takes to burn one pound of fat. Divide this number by 3,500 to determine the number of pounds of fat you lost.
Tips and Warnings
- When you exercise at 50 to 60 percent of your maximum heart rate your body burns 70 to 85 percent fat. Exercising at 60 to 70 percent MHR burns 50 to 70 percent fat; 70 to 80 percent MHR burns 40 to 60 percent fat; 80 to 90 MHR burns 10 to 20 percent fat; and 90 to 100 percent MHR burns 10 to 15 percent fat.
Things You'll Need
- Heart monitor
- MET chart
References
- Hospital for Special Surgery; Burning Calories with Exercise: Calculating Estimated Energy Expenditure; November 2004
- Heart Zones; How to Enlarge Your Fat Burning Range with Heart Zone Training; July 2001
- MayoClinic.com; Counting Calories: Get Back to Weight Loss Basics; Mayo Clinic Staff; December 2009
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