The Oxidative System
Two weeks ago we discussed your creatine phosphate system and its importance to your exercise routine. We took a look at how carbohydrates are affected by training and why you need to be eating enough.
This week we are going to do a brief overview of the next energy system, the oxidative system. Once we get through this we will be well prepared to put it all together next week. That’s when you are going to realize just how important this ‘boring science stuff’ is to all of you.
Here is the basic rundown. Once you go over about 60 to 90 seconds of exercise your body switches from glucose for energy to what is known as your aerobic metabolism. You start to use oxygen to produce energy is how things go in the most basic sense.
You have most likely heard of your target heart rate zone. If not, just think about those neat little stickers on treadmills and elliptical that show where your ‘fat burning zone’ is. That’s your oxidative system at work. Using oxygen and body fat to fuel exercise.
Wait you are thinking, burning body fat for energy? That sounds great. It is great. And when working at these intensities you will preferentially use body fat for fuel. Next week we will compare the oxidative and glycolytic systems with each other.
When do you use this energy system? Essentially, during any exercise that goes longer than 30 to 45 minutes is when this form of energy metabolism will take over. When you go for a run, get on the treadmill or elliptical, or any other form of low intensity, long duration exercise this is how you will be fuelling it.
Now, while the idea of burning fat for fuel seems idyllic, there are a few other things to think about. All the benefits of increased metabolism, improved hormone balance, elevated metabolism, and being able to better utilize carbohydrates do not happen as a result of training within the oxidative system and protocols.
In fact, chronic use of your oxidative system as an exclusive method of training will actually SLOW your metabolism down and increase your ability to store excess body fat.
Overall calories burned by your body from this type of exercise are actually less than the glycolytic exercise system we discussed last week when looked at over the course of 36-72 hours.
Lastly, important to note is that any workouts that take longer than 50 minutes or so (I am purposefully being general in an effort to keep this applicable to all, there are many variables to all of this energy system stuff) you are going to begin to utilize this energy system as opposed to your glycolytic system. So even if you think you are doing high intensity exercise training or strength training, you are not really if you are going over 45 – 50 minutes of training. Then you are working in your oxygen based energy and low intensity training system.
I know, this has been a little dry for a couple of weeks. It is important, I promise. And next week I will put it together and tell you why!