Did you know that there are three different pathways through which our body uses energy during exercise? All dependant on the type of exercise? Which pathway is used mostly depends on the intensity and duration of the exercise ie a gentle walk vs an all out sprint.
First off we have the so-called ATP-PC system. This is the energy system that is favoured during very short and high intensity bouts of exercise. Think of an all out effort of 10 seconds or less.This energy system doesn’t require any oxygen and it is depleted very quickly because it relies on bodily stored energy (ATP) and creatine phosphate in the muscles.
Secondly we have the Glycolytic system. This is the energy system that gets activated for efforts that are a bit longer, ie 30 seconds to 2 minutes and it also doesn’t require any oxygen, just like the ATP-PC system. However, the glycolytic system uses glucose, which it gets from carbohydrates, to form energy (ATP). If you haven’t eaten any carbohydrates before your workout, your body will have lower than ideal stores of glycogen, meaning your performance will suffer because it will not have the fuel needed to perform.
Thirdly, and finally, we have the oxidative system. This energy system is used during longer, low intensity forms of exercise. It uses oxygen to convert bodily stored carbohydrates, as well as fat into energy. This energy system helps us to go for long!
It is important to note that our body never uses one system exclusively, but rather uses a combination of the above pathways. How much of each pathway is used, depends on the activity as a whole. For example if you are running a marathon, your body will primarily be generating energy through the oxidative system, but there will likely be times where you run a bit faster, and then the body will tap into the glycolytic system.
Knowing how our bodies generate energy during exercise, can help us get to know our bodies better when it comes to performing, and fuel for the work required.