Low Intensity Vs Higher Intensity Cardio

I have received several follow up questions on the posts that I wrote earlier on cardio vascular training, so I am going to elaborate a little more on that.

We are going to look at lower-intensity vs higher-intensity, not interval training per se.

One of the reasons that people have a hard time changing the way they think about cardio vascular training is because of past media attention to the 'fat burning' zone. The fat-burning zone does exist, well, sort of. Yes, the body burns a greater percentage of fat at lower-intensity aerobic training, not a greater amount of fat. That's where all the confusion comes into play.

Working out at a lower intensity may burn 50% of your total caloric expenditure in fat, and working out at a higher intensity may burn 35% of your total caloric expenditure in fat. That looks like you should keep going at in the lower intensity range, right? Well, let's look at the numbers:

A 150 pound woman who is reasonably fit gets on the elliptical trainer for 45 minutes at a low intensity (reading her Cosmo or watching TV - this is the most likely scenario in any health club). She has been doing this same thing for, let's say, six months now. During that 45 minutes she burns approx. 200-300 calories. *The machine will say she has burned more, but in reality she is probably burning a little less every time she performs the activity because her body is used to it.* Of that 200-300 calories, she has burned 100-150 calories of fat, based on the above equation.

Now the same 150 pound woman hires me as her trainer (very smart woman). The elliptical is a safe piece of equipment (my least favorite) so we stick with it. To make it simple, before I really start to push her, I ask her to select the interval or hill program listed on the machines console. I also ask her to forward through all the prompts asking for her age, weight and sex. The machine is supposed to be able to figure out how many calories you burn with that information which is absolutely ridiculous. Does the machine know your resting heart rate? Does the machine know how much muscle you have? Does the machine know if you are on medication? Didn't think so.
Anyway, we get her going and I monitor her exertion by asking her how she feels, but I also watch her. If she starts to look around the gym at the other members during the higher intensity segments, I increase the intensity. If she is focused, we stay at the same intensity. I do not expect her to go at a high intensity for the full 30 minutes. If your mind is wondering, you are not pushing yourself hard enough.

Now she has burned approx. 300-400 calories, 100-150 of them from fat. She has burned the same number of calories from fat but in a lot less time. As long as she monitors her intensity, and she doesn't start zoning out (which will lower her caloric expenditure), she will continue to burn more fat. Next step would be interval training to bump that fat burn even more.

Remember, this is not INTERVAL training, this is just increasing the intensity of your cardio vascular training. I will write more about interval training later. This is a great place to start learning why increasing the intensity of your cardio vascular workout is so great for your fitness and fat loss goals.

All you have to remember is: If you can read a magazine while working out, you might as well get off the machine.