I have been doing interval training for my cardio workouts for quite a while as I thought this was the best way to achieve and maintain a good level of non-sports specific aerobic fitness. I read today though that anaerobic training or interval training has no real improvement in your cardiovascular level of aerobic fitness. So should I switch from this to gain and maintain a good level of aerobic fitness and instead do medium distance jogging for three to five miles?
That is actually a great question with a million correct answers. However, how you phrased it really shows that you are heading in the right direction. First, I would say that it depends on your level and “definition” of intervals. While the majority of my career has been working with athletes, we always used intervals to increase the body’s ability to maintain and/or increase one’s level of lactic acid capacity. A good example for lactic acid in the body is a bathtub. Imagine that the facet is the lactic acid, and the drain is your body’s ability to remove the lactic acid from the muscles (the lymphatic system.) The more the facet is turned on, the more quickly the tub begins to fill, and the more lactic acid is released into your muscles. However, the greater condition your heart and anaerobic system is in, the more quickly the drain can empty the water, or the more quickly your muscles can get rid of the lactic acid. If the water reaches the top of the tub, then that person’s lactic acid threshold has been met. With this example in mind, now look at an athlete who is well conditioned and look at an everyday person. Whose bathtub is going to overflow first?
I am aware that this was not necessarily your question. However, I felt it was important to give you an understanding of the theory behind interval training. Now for your specific case, if you are looking to increase your aerobic capacity, then yes, it is important for you to exercise more aerobically. The major difference is going to be your body’s maximum exercise heart rate. Once your body’s heart begins to beat at a high enough level, you start to create the lactic acid (at a higher level) I spoke about in the previous paragraph. Thus, you are no longer in an aerobic training zone. There are basic calculations an individual can do to learn his aerobic heart rate (220-age and then 65-80%.) However, my personal opinion is that you should switch between the two. Not only will it prevent boredom, but interval training also constitutes a higher heart rate (hence, anaerobic) and therefore can burn more calories at a faster rate. You might remember the instructor in the spin classes at your gym talking about how one can burn more calories there than any other class. That is because you are constantly switching between an anaerobic and aerobic heart rate. It is the law of thermodynamics: the higher the heart rate, the more energy/fuel is needed, and in this case, the fuel is calories. Lastly, since you are a personal trainer, I feel it is advantageous of you to do both aerobic and anaerobic for your client’s sake. When he or she asks you the difference between the two and/or which one you prefer, you can answer from experience.
Deciding what exercise is best for you really depends on your goals of exercise. Just remember that one is aerobic, and the other is not.