Exercise and oxygen consumption are directly linked. To meet the demands of increasing exercise intensity, your body must use more oxygen to produce energy. Exercise research labs often use oxygen consumption to determine how many calories are being burned in a workout.
Werner and Sharon Hoeger’s book “Principles and Labs for Fitness and Wellness” states that 1 liter of oxygen consumed burns five calories. Using this value in conjunction with the MET scale can help you determine how many calories you are burning when you’re workout out.
METS, or metabolic equivalents, are used in exercise prescription to dictate intensity levels. Common MET levels are 3 METs for walking slowly, 6 METS for biking at 10 to 12 mph and 8 METS for jogging at 5 mph. One MET is equal to a relative oxygen consumption of 3.5 mL/kg/min.
To determine how many you are burning, multiply the MET value by 3.5. Multiply this by your bodyweight in kilograms to get the amount of milliliters of oxygen you’re consuming per minute. Divide this by 1,000 to get the number of liters per minute you are consuming. Multiply by 5 to get the number of calories per minute you are burning. Multiply by the number of minutes you have worked out to determine how many calories you burned in a single exercise bout.
If you weighted 200 pounds, biked at 10 to 12 mph, or 6 METS, for 30 minutes, your calculation would look like this: 6 X 3.5 X (200/2.2) / 1000 X 5 kcal X 30 = 286.4 kcal burned in that particular workout.