Energy For Everything You Do
You’ve probably heard of aerobic and anaerobic respiration, which essentially refer to energy with oxygen (aerobic) and without (anaerobic). Aerobic respiration is the basic, constant type of energy that you’re supplied with. You breathe, flooding your arteries with oxygen-rich blood, which takes care of your body’s basic functions When you aren’t spending a lot of energy, aerobic respiration is sufficient by itself.
Once you start doing more extraneous fitness activities, such as walking the amount of oxygen in your blood becomes less capable of supplying enough energy. Walking isn’t too bad, but then you start running, lifting weights, or swimming. You’re breathing very hard because your body realizes that you need more oxygen, but in most cases, this still isn’t enough.
At a certain level, anaerobic respiration begins to take over. Because oxygen is not used to supply energy, your body turns to molecules like carbohydrates to meet its demand. Each of these is part of the ATP (Adenosine triphosphate) cycle, which supplies all of your body’s energy. Understanding the ATP cycle is critical to weight loss.
The Oxidative (Aerobic) System
As previously mentioned, the oxidative, or aerobic, system uses oxygen to produce ATP. There are a number of biological systems at work here, chiefly the Electron Transport Chain (ETC) and the Krebs Cycle. Without going into details that could fill an entire chapter in a biology textbook, these two cycles detail how oxygen in the blood connects to hydrogen molecules in stored energy compounds, like body fat.
When a hydrogen molecule breaks off, it creates a small amount of energy, which is needed for the ATP cycle. First, let’s take a quick look at the basics of the ATP cycle.
ATP stands for Adenosine triphosphate (three phosphates), and ADP stands for Adenosine diphosphate (two phosphates). There is a lot of ADP floating around in your blood, but it’s at a stable, low power state and supplies no energy. ATP, on the other hand, supplies all of your body’s energy.
When you’re doing fitness exercise of any kind, you want to to produce a lot of ATP. ATP requires ADP to bond with another phosphate molecule. Think of ADP as A+P+Pand ATP as A+P+P+P. To get to ATP, you need to add a P, or one phosphate. That takes energy, which is where the ETC and Krebs Cycle from the beginning of this section come into play.
How does any of this relate to weight loss? Well, don’t think of weight loss as “burning fat,” a term which causes a lot of misconceptions. Instead, you’re simply breaking down stored energy molecules, like carbohydrates, to generate ATP molecules from ADP.
The whole time, your muscles have been crying out for energy. Once an ATP molecule passes through muscle, one of the phosphates breaks off from the ATP, creating an ADP molecule once again. Remember, energy went into binding the ADP and phosphate together, and when they separate, energy is released into your muscles
If this sounds like a fairly complex system, don’t worry. There’s really only one thing you need to know about aerobic respiration —the more oxygen that you can supply to yourself, the better off you’ll be.
That’s why aerobic exercise is so important to people. Not only is it great for losing weight (because your body has to produce a lot of ATP), but the very strain that you put on your lungs to draw in huge amounts of air make them stronger. Your heart also becomes more efficient as it learns to pump more oxygen into your body.
