People ask me all the time: How do I lose weight? It’s actually just math. You have to burn more calories than you take in. It’s pretty simple to calculate how many calories you take in…just start a food journal and measure your food with a food scale. But how do you calculate how many calories you burn? That’s a little bit trickier. If you don’t have a fancy device like a body bug, you’ll have to do some more calculating.
The calories that you burn throughout the day depend on your basal metabolic rate (BMR)…you can find a formula for calculating that here: http://www.bmi-calculator.net/bmr-calculator/
Then, you’ll need to add in the calories you burned during your workout. In order to do that, you’ll need a heart rate monitor. The calories you burn during exercise depend primarily on your heart rate during the exercise. Other important factors for your calorie expenditure include your gender, age and weight. Each gender uses a specific formula to calculate calorie expenditure while exercising. Your calorie expenditure is an essential factor in predicting your weight-loss rate during a fitness program.
Calorie expenditure relies more on your heart rate than the specific exercise. This allows you to use the same formula to calculate your calorie expenditure during any form of exercise. The formula is most accurate when you keep your heart rate between 90 and 150 beats per minute, or bpm.
A heart monitor can record your average heart rate during exercise and the duration of that exercise session. A bathroom scale can provide your weight. The calorie expenditure formula requires you to provide your heart rate in bpm, the duration of the exercise in minutes, your weight in pounds and your age in years.
FORMULA
(if you want to skip the crazy math…keep scrolling down…I don’t want your head to hurt =))
The Journal of Sports Sciences provides a calorie expenditure formula for each gender.
Men use the following formula: Calories Burned = [(Age x 0.2017) — (Weight x 0.09036) + (Heart Rate x 0.6309) — 55.0969] x Time / 4.184.
Women use the following formula: Calories Burned = [(Age x 0.074) — (Weight x 0.05741) + (Heart Rate x 0.4472) — 20.4022] x Time / 4.184.
CALCULATION
Let’s say you’re 32 years old and you weight 173 lbs. for this example. You’re male and your average heart rate during a 37-minute exercise session was 133 bpm. Your calorie expenditure during this exercise session was [(32 x 0.2017) — (173 x 0.09036) + (133 x 0.6309) — 55.0969] x 37 / 4.184 = 174 calories.
ESTIMATE
The Mayo Clinic provides calorie expenditure estimates for a variety of activities and body weights. For example, a person weighing 160 lbs. will burn 584 calories by jogging at 5 mph for an hour. Running at 8 mph for an hour burns about 986 calories if you weigh 160 lbs. Walking at 3.5 mph for an hour burns about 277 calories for a 160 lb. person.
Yup…looks confusing to me! You can also find a website like this one: http://caloriecount.about.com/tools/calories-burned and plug in your gender, age, height, weight and activity level and they do all that calculating for you =)
If you ARE serious about your weight loss, I highly recommend getting either a body bug or a fitbit…something that can SHOW you every day how much you’re moving. It’s a GREAT motivator…once you see those numbers you’ll know how much you need to move every day to hit your target, and then lose weight.
I hope this guide helps you to understand how to calculate your calorie burn during exercise. Remember–we are ALL different…this is going to be YOUR calorie burn. Not mine. It all depends on your height and weight. I might burn 600 calories doing an hour of cardio while you only burn 400. I’m 6’1” and weight more than most girls. The more you weigh, the more calories you burn.
REFERENCES
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Mayo Clinic: Calories Burned in 1 Hour
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Journal of Sports Sciences: Prediction of Energy Expenditure from Heart Rate Monitoring During Submaximal Exercise
