Running is one of many ways that can help you meet the 150 minutes of aerobic exercise suggested by the Centers for Disease Control and Prevention. When it comes to running, you have two main choices available to you -- indoor running on a treadmill or running outside on a road, track or trail. However, the location alone is not enough to determine which burns more calories. There are several other factors to keep in mind that can affect the amount of calories you can burn per hour.
One the major factors in how many calories you burn while running is the incline of the surface you're running on. The higher the incline, the harder your muscles have to work to continue at the same pace. The harder your muscles work, the more energy they burn, resulting in a greater calorie burn as the muscle cells work to replace used energy. With indoor treadmills, you can change the incline by setting the incline number on the treadmill's dashboard. With outdoor running, you just need to find hills to run up to increase the calorie burn.
Speed can also determine whether a treadmill or outdoor running will burn more calories. On a treadmill you can more easily set a specific speed and stick to it, as the speed you set is what speed the treadmill track will move at. With outdoor running your speed can vary, since you are relying more on your internal sense of speed instead of a machine. Just like incline, the faster you run, the more energy your body uses up, resulting in a greater calorie burn to replace used up energy and maintain your running speed.
Where running outside starts to have an advantage over treadmills is the changing outdoor environment, such as wind. When on a treadmill, the only wind you may experience is the blowing of the air conditioner or fan. This does not create a lot of resistance against your body. However, outdoors, you can face varying levels of wind speed, which creates resistance against your body. The more resistance your body faces, the more the muscles work, and the more calories your body burns per hour.
Benefits and Disadvantages
Beyond the amount of calories each method burns, it's also important to take into account the benefits and disadvantages of each running method. Indoor treadmill running has obvious advantages, such as being able to exercise whenever you want, regardless of the weather outside. Treadmills also have a padded surface, which can help reduce impact on the knee joints. However, treadmills have a flat surface, which takes away your body's natural propreoceptive training, or your body's ability to sense both the motion and position of your body in relation to the environment, which can negatively affect you if you are training for an outdoor running event, like a marathon. Outdoor running also can provide a more entertaining and engaging workout, as the environment consistently changes as your run, making the exercise less boring.