Calories Burned From Running

Just how much ice cream a runner can eat after a 10K race may not be the wisest thought process, but running burns calories. Curiosity prompts most runners to make an occasional calorie-deficit calculation. You can figure out approximately how many calories you burn in a workout. Factors that affect calorie expenditure include your weight, speed and workout intensity.

Scientifically Speaking

Keep in mind that the only extremely accurate way to know how many calories your metabolism expends in a specific span of time is to discover your VO2 max--maximum amount of oxygen your body can consume in a minute: your aerobic capacity. Next, you wear a monitor to measure and chart how each segment of your workout compares with your VO2 max. From these numbers you derive your calorie expenditure.

Generally Speaking

Though each body is different, some simple equations can help a runner calculate the energy spent in a single workout. Several calculation schemes exist, but that devised by the American College of Sports Medicine's (ACSM) has been validated by several controlled studies. It provides ways to estimate gross and net calories burned, that is, the total calories spent (gross) and the total extra calories--the energy a runner expends on top of her resting metabolic rate. Its estimates are trustworthy.

Math

The ACSM scheme assumes a moderately intense workout and averages across paces. Using this scheme to find the total calories burned per mile, multiply your weight by 0.75. To find, instead, the net calories per mile, multiply your weight by 0.63.
Weight (in lbs.) x 0.75 = Total Calories Burned per Mile Run
Weight (in lbs.) x 0.63 = Net Calories Burned per Mile Run

What's Your Pace?

That said, it's true that if a runner works harder, he consumes more oxygen: more calories. So an intense workout--sprints, time trials, hill and stair workouts or running on soft sand--burns more calories.

Resting Metabolic Rate

Regular exercise often affects a runner's basic metabolic, setting it to burn more calories even when not running, for about 24 hours after an exercise session. This rate heightening corresponds to the intensity of exercise. The increase in basal metabolic rate is most pronounced during the first 12 hours.