Burning calories means you can afford to eat more, which is especially helpful if you are trying to manage your weight. You may think the more calories you burn during a workout the better, but the quality of your workouts is really what counts toward your fitness and health goals. An emphasis on calorie burn as a measure of the effectiveness of your workout is actually quite shortsighted and may undermine your goals.
It Depends on You
How many calories you burn during a workout depends on numerous factors, including your size, intensity level, fitness level, activity and body-fat ratio. For example, a 125-pound person walking for 30 minutes at a brisk 4 mph burns 137 calories in 30 minutes, while her 185-pound friend burns 200 calories in that same amount of time. What constitutes a good calorie burn for you isn't necessarily what constitutes a good calorie burn for everyone else. If you are at a healthy weight and your friend is overweight, he may burn more calories doing the same workout -- but that doesn't make his session "better" than yours. Beginners may not achieve the fast runs and vigorous intensities required to burn 500 or more calories in an hour, and that's OK. Over time, you can work up to a higher burn rate, but be patient; going too hard, too soon in an attempt to burn a large number of calories can lead to burnout and injury. Your goal should be to increase physical activity, not to achieve a particular number of calories burned.
Calories Aren't Everything
Oftentimes, weight loss is the goal of exercise. Burning 3,500 calories leads to the loss of one pound, so you may become fixated on reaching as high a number as possible during your workouts to lose weight as fast as you can. Cardio activities, such as jogging, cycling and aerobic dance, tend to give you the biggest calorie burn -- about 200 to 400 per half hour for a 155-pound person. Calories burned isn't the only measure of a good workout, however. Resistance training, which helps change your body composition so you have a greater amount of lean muscle tissue, burns fewer calories than cardio. However, when you have more lean muscle, you look toned and fit and burn a slightly greater amount of calories at rest. A paper published in a 2012 issue of "Current Sports Medicine Reports" notes that just 10 weeks of regular resistance training can increase your metabolism by 7 percent and reduce fat. A 155-pound person may burn only 112 calories per 30-minute session, but this doesn't take into account the other benefits of that workout.
Determining a good calorie burn for a workout isn't easy because of the inaccuracy of machines. Machines, such as ellipticals, can be off as much as 25 to 30 percent either way, says John Porcari, a professor of exercise and sport science at the University of Wisconsin in La Crosse, as reported in the "Los Angeles Times." Precise determinations of your calorie burn can only be done in a special scientific setting in which scientists measure the heat your body releases; everything else, from heart rate monitors to calorie-counting gadgets, provides mere estimates. Instead of focusing only on the number of calories burned, tap into how you're feeling during the workout. Alternate measures such as heart rate and perceived exertion can tell you if you've had a good workout. Also consider your calorie burn over time. If during week one you burn 200 calories per 30 minutes on the elliptical, but are able to increase that to 250 during the next week, you know your fitness level is progressing and you're working harder.
Beyond the Burn
Fitness provides numerous benefits beyond calorie burn. You release feel-good chemicals that improve your mood. Daily activities are easier when you are fit. You protect yourself from injury and chronic disease. Exercise helps you sleep better and can improve your self-esteem.