If you've resolved to build a healthier body, a long list of aerobic activities can help you get results. Two such exercises are walking and bicycle riding, each of which helps you burn calories as you attempt to lose or maintain your current weight. In each activity, your weight and the exercise intensity influence how many calories you can expect to burn.
Walking burns calories at a slower pace than bicycle riding. If you weigh 155 pounds, walking for half an hour at a pace of 3.5 mph will help you burn 149 calories. As you increase your pace, you increase your caloric burn; 30 minutes at 4.5 mph burns 186 calories for the same person. Race walking is a better workout; 30 minutes of this activity helps a 155-pound person burn 242 calories. A person of the same weight who rides a bike for the same duration burns far more calories. At a speed of around 13 mph, the same person burns 298 calories. If she increases her pace to around 15 miles per hour, she'll burn 372 calories. You can measure your speed using methods such as a pedometer, smartphone app or a bicycle speedometer. A lighter body weight results in a slower caloric burn, while a heavier weight means you'll burn calories quicker.