Your metabolism, in short, is responsible for turning available energy sources into usable fuel to enable movement, exercise, and general bodily functions. Without enough energy, not only will we struggle to perform basic activities, our organs could begin to operate sub optimally resulting in rather dangerous health complications. Therefore, your metabolism is obviously super important and as such, the miracle of nature that is the human body has a few options. By far the most common energy supply within you is your aerobic metabolism.
What Is Your Aerobic Metabolism
The term “aerobic” in the context of your metabolic functions, refers to your body’s utilization of oxygen. Aerobic respiration (you may know it as breathing) allows oxygen into your blood. Oxygen is used by humans for glycolysis (The burning of glucose for energy), and lipolysis (the burning of body fat for energy).
Thankfully, we breathe on autopilot so we constantly allow a flow of oxygen to unlock the fuel we need to keep us alive. Whether we like it or not (of course we do), our aerobic metabolism is active and it is allowing us to do everything we are doing. Every thought we have is possible because of the energy in our brain. Your daily footstep targets are achievable because of the energy supplied to the muscles in your legs. The button on the TV remote can only be pressed because of the energy supplied to the muscles in your fingers. I could go on but I trust you get it.
What Is Aerobic Glycolysis
When you eat, your body recognizes 3 macro nutrient groups and reacts differently to all three. As the body’s emergency choice for energy, the molecular make-up of protein serves a much more important role in your bodily functions. Fat is your body’s second choice for energy but glycolysis is the process of your body using carbohydrates for energy.
The carbs you eat will be processed in your stomach and turned into glucose which will be sent into your bloodstream. If I was going to explain the full scientific process, there would be a lot of steps in the energy intake to usage cycle, of which glycolysis is merely the first. However, because you don’t need to know every little detail (and I don’t know all the big words involved), I will keep it high level.
Several chemical reactions will take place involving blood oxygen and blood glucose which will rearrange the chemical compounds of the food you have eaten into usable energy. Your pancreas will create enough insulin to transport this energy to where it is needed which will be all of your organs and muscles. How much energy they need will be dependent on how active you are.
What happens next will be dependent on how active you are due to your energy balance and your glycogen reserves
Glycogen Reserves & Energy Balance
Unless your body is in the metabolic state of ketosis (I am not going to explain ketosis as I am strongly against it for people without access to professional fitness and nutritional support), it knows it will be more efficient at burning carbohydrates for energy than anything else. So despite excess “energy” being stored as body fat, you will have a bit squirreled away in the form of glycogen in your muscles and liver.
If you have been quite active, your glycogen reserves will be depleted, in which case your body will “restock” once you have utilized the energy needed for immediate use. If you have not eaten enough prior to your activity you will have a negative energy balance and the level of activity required to deplete your glycogen reserves may be less. Therefore, it is important to eat enough carbohydrates after exercise to replenish your glycogen levels.
If you have eaten too much and/or have been quite inactive, you will have a positive energy balance or a caloric surplus. This means the amount of energy needed immediately will be less, and your glycogen reserves will be unlikely to need replenishing. Any excess energy in your bloodstream will be stored as body fat for use later as required.
We all know that body fat can cause health complications if we store too much for too long. However, maintaining somebody fat is essential as it protects our nervous system and gives us energy when we are not eating (most commonly when you are asleep).
What is Aerobic Lipolysis
When you are out walking and you decide to pick up the pace, you will require more energy for the additional effort expended. Your blood oxygen levels will rise and in order to fit more in your circulation speeds up. With your blood rushing around your body, the extra oxygen will go unlock the energy in your fat stores and your bloodstream will transport it to your brain, heart, lungs, muscles and everywhere else it is needed.
While your body can burn fat and carbs for energy simultaneously, insulin inhibits lipolysis so it will only really be efficient at one or the other at any one time. If aerobic lipolysis is necessary during exercise due to your increased energy expenditure, it becomes necessary as the best available energy source after a period of not eating.
We can only really burn glucose or fat that we have available and where your blood glucose levels are on a time limit before excess gets stored as fat, your body fat will wait around for as long as it takes to be used.
For this reason, a lot of people like intermittent fasting because you will not get physically hungry if your body is not looking for carbohydrates and has reserves of fat. I love intermittent fasting but it is important to remember, you still need a negative energy balance to lose weight or any body-fat burned will be replaced when you do eat.
Your Aerobic Metabolism Keeps You Going
We all know oxygen is imperative to our survival, but did you realise it was because oxygen is essential for the body’s use of energy. Every breath you take is not only keeping you alive, it is giving you the life. If you get out of breath while you are out walking, this is a good thing. Your body is taking in more oxygen so you can use more energy.