To clear up a couple of very, very misconceived notions about exercise and how it affects the body, we will add a quick note on how exercise intensity and rate play a major role in the amount of calories burned.
Notion 1: Walking vs. Running a Mile: Many people are under the impression that an individual burns the same amount of calories walking a mile as they do running a mile. That is FALSE. Without a doubt, you burn more calories when you RUN a mile as opposed to when you walk a mile.
Notion 2: Exercise Rate and Intensity: Also, many people seem to think there is a magical formula that applies to every single person (regardless of age, height, weight, and fitness level) that whenever you run 1 mile, you burn exactly 100 calories. That is possible if someone traveling at the proper speed with a certain weight, age, and height were to run a mile, but the majority of people travel faster than that, and do not fit the other factors to hit the 100 calorie mark. In almost all situations you burn MORE than 100 calories per mile.
When it comes to the idea that running and walking a mile burn the same amount of calories, here’s the correct information on that: When an individual performs a continuous exercise, they burn five calories for every liter of oxygen consumed. Since an individual consumes more oxygen while running than they do walking, more calories are burned just from the aspect of oxygen consumption.(Burfoot, Amby. “How Many Calories are you Really Burning?” www.runnersworld.com)
Next we will touch on the topic of exercise rate and intensity. (Compare this example to other aspects of working out like strength training, the harder you work your muscles, the more calories burned and strength gained.)
When an individual walks, they generally keep their legs mostly straight, and their core/center of gravity remains fairly straight on top of their legs. In running, they actually jump from one foot to the other. Each jump raises their core and legs when they take off, and lowers then when they land, since the knee bends to absorb the shock of impact. This constant rising and falling of our weight requires a tremendous amount of force on both the takeoff and landing; therefore, requiring the muscles to work harder. This in turn requires more oxygen consumption because the heart must work harder in order to deliver Oxygen to the working muscles (inspiration/inhaling) and more importantly, to remove the extra hydrogen ion released into the blood stream from the working muscles to reduce the lactic acid build up in the working muscles (expiration/exhaling). .(Burfoot, Amby. “How Many Calories are you Really Burning?” www.runnersworld.com)
So the harder your muscles are working, there is an exponential increase with the amount of oxygen consumed and carbon dioxide released. To tie in a constant elevated heart rate to the above, the more you run the more calories you burn: The above listed is all seen with an increase in heart rate during exercise, which would not occur if the muscles were not working harder/at a higher rate requiring more oxygen to be delivered and lactic acid to be removed (which equals boost in metabolism and more calories burned!).