In technical terms, a calorie is a unit of heat measurement. If you're counting calories in an effort to gain or lose weight, you will want to take into account how many calories you burn while exercising - although it's important to note that people burn far more calories daily in basic biological functioning than they do through intentional exercise. The number of calories you burn depends on the intensity of the activity as well as your body composition.
Estimating Calorie Burn
Estimating caloric expenditure can be helpful in keeping your energy balance in check, but it's a fairly inexact science on a day-to-day basis. It's different for scientists in labs complete with equipment specific to the task, but for the layperson, a credible online exercise calorie calculator can provide good estimates.
The metabolic equivalent (MET) is a measurement of oxygen utilized in an exercise; at rest, MET is 3.5 ml of oxygen per kilogram of body weight per minute. The American Council on Exercise suggests this equation to discover the number of calories burned in a specific exercise per minute:
METs x 3.5 x BW (kg) / 200 = Kcal/min
Essentially, the formula takes into consideration an individual's MET multiplied by 3.5, multiplied by body weight (in kilograms), divided by 200, resulting in the number of calories burned per minute. Note that gender is not a factor in this equation.
The level of intensity during exercise has a profound impact on the number of calories burned. The harder you work, the more oxygen you consume - and therefore, more calories expended. That's why it's important to take intensity into consideration; an activity doesn't have a specific calorie count attached to it regardless of intensity. For example, while dancing can be a good cardiovascular workout, the intensity of the activity changes the calories burned. A person who weighs 165 pounds and dances for 30 minutes can expect to use around 133 calories when waltzing but the same person will use around 281 calories in a dance fitness class like Zumba.
Calories Burned Calculators
If the thought of working through an equation for each activity to estimate your calorie expenditure doesn't appeal to you, try one of the many calorie calculators found online. Many of them also include food calorie databases so you can track your energy balance (or imbalance) daily in an effort to lose, gain, or maintain your weight.
One of the most popular calculators available online (or as an app), MyFitnessPal tracks your caloric intake alongside your caloric expenditure. Access to both the food and expansive exercise database are free and the community is quite active via forum discussions, blogs, and the ability to "friend" other users, similarly to a social media platform.
WebMD Exercise Calculator
WebMD offers a simple exercise calculator that is quick and simple to use. Select an exercise from the database, input your weight and the duration of the activity to receive a quick estimate of calories used. Some of the exercises in the database allow you to specify intensity (light effort, moderate effort, brisk effort) to further clarify calories used.
VeryWell Fit offers a free calculator that requires your weight, the duration of the exercise, and the selection of an exercise from the calculator's database. What makes this simple calculator stand out among the others is the activity-specific advice provided with each calculation. For example, inputting 30 minutes of softball results in the calories burned along with advice on avoiding common softball injuries.
Calories for Popular Activities
The following estimates are for a 165 pound individual doing 30 minutes of the activity:
- Walking slowly: 94 calories
- Walking at a race pace: 244 calories
- Bicycling at a leisurely pace: 150 calories
- Mountain biking: 319 calories
- Swimming at a leisurely pace: 263 calories
- Swimming vigorously: 375 calories
- Yoga (body flow): 169 calories
- Yoga (power): 263 calories
Though counting calories (either consumed or expended) isn't necessarily an exact science for those outside of a laboratory, the practice can still be a good guide to help you decide on your daily activities. The more intense your effort, the more calories you will utilize in the activity.