The amount of calories you burn in any exercise depends on your level of intensity, the duration of your workout and your body weight. Exercises that are inherently more vigorous, such as running, burn a higher amount of calories in a shorter amount of time than less vigorous workouts such as walking. However, you can perform any exercise until you burn about 500 calories. Burning 3,500 more calories than you consume each week can lead to a weight loss of about 4 lbs. per month.
A lighter person must work harder or for a longer period of time to burn 500 calories than someone who weighs more. Working out for an hour at moderate intensity, a 120-lb. exerciser can burn approximately 500 calories on the stair treadmill, in a step aerobics class or a boxing workout. In a 45-minute workout at a vigorous effort level, the same exerciser burns about 500 calories cycling, rowing or running an 8-minute mile. In less intense 75-minute workouts, a 120-lb. exerciser burns around 500 calories jogging, in an aerobics class or swimming laps.
During moderately-intense workouts lasting an hour, a 150-lb. exerciser burns about 500 calories jogging, biking outside or on a stationary bike, rowing or in a high-impact aerobics class. Playing touch football or soccer for an hour will also burn approximately 500 calories. A 150-lb. exerciser who wants a shorter workout can burn 500 calories in 45 minutes by running at a 10-minute mile pace, biking at about 15 mph or doing step aerobics with a 10-inch bench. To burn the same amount of calories with less intensity, the same exerciser can walk 4.5 miles in 75 minutes, or swim easy laps for 75 minutes.
At 200 lbs., an exerciser doesn't have to work quite as hard to burn 500 calories. In an hour, a 200-lb. person can walk just over 4 miles, take a low-impact aerobics class, or perform a moderately intense circuit training workout to expend 500 calories. In 45 minutes, the same exerciser reaches the mark by running at a 12-minute mile pace, or biking or rowing with moderate intensity. During an even shorter, 30-minute workout, a 200-lb. person burns approximately 500 calories biking vigorously or running at an 8.5-minute mile pace. For a less-intense, 75-minute workout, the same exerciser burns 500 calories shooting hoops.
Overweight people tend to lose initial pounds more quickly than those who have just a few extra pounds to lose, in part because they burn so many more calories during an equivalent workout. For example, someone who weighs 250 lbs. burns 500 calories over the course of an hour of biking at a semi-leisurely pace, or walking 3.5 miles. Although it can be more challenging for a heavier person to run, a 250-lb. exerciser expends approximately 500 calories in a 45-minute jog. Swimming laps for 45 minutes, free-style, results in the same calorie expenditure.