First of all, we have to answer the question, what is aerobic and anaerobic exercise?
I'm going to give you the simple answer. Aerobic exercise means in the presence of oxygen, and anaerobic means without oxygen. How that translates to exercise is simply this, when you are exercising aerobically, you can breathe and you can talk in at least a sentence at a time--you are exercising "with oxygen". When you are exercising anaerobically, you can't breathe and you can only utter a word or two without having to take another breath--you are exercising "without oxygen".
There are all kinds of things that happen to your body physiologically, but this is really all you need to know.
I think the picture below describes it perfectly. The runner on the right is working aerobically and at a steady pace. The shadow on the right is what the runner would look like if they just sprinted all out to the finish line, gasping for air.
So, which is better? My personal answer to that is neither. They are both important and they both serve different roles when it comes to health and fitness.
Aerobic exercise is usually done for a longer period of time at a steadier pace. Examples of this would be long distance running/jogging, walking, an aerobic exercise class such as step or zumba, swimming and biking. The reason that this type of exercise is good is the fact that it can be done for a longer period of time, therefore increasing endurance. Also, oxygen is needed in order to burn fat, so when working out aerobically, you are also burning fat--but more about this in a future post.
Anaerobic exercise is done in bursts. For example, many sports are anaerobic because the running and/or jumping is done in spurts--soccer, football, basketball, tennis--the pace changes from slower to faster--it would be impossible to keep up the super fast pace the entire game. This type of exercise challenges the muscles--especially the heart; the increase and decrease of heart rate is a workout in itself. This type of exercise also burns more calories because more energy is needed and expended to do it. But, because it's so hard to maintain this type of intensity, an anaerobic only workout would have to be relatively short in duration.
My solution? Do both. Mix up your workouts to include both aerobic and anaerobic exercises and here are a few ways to do that.
1. Do Intervals. During an interval workout, the pace/intensity changes at set "intervals" throughout the workout. For example, during a walk, you would walk at a very fast pace for 1 minute followed by a slower pace for 2 minutes. This is usually a strictly cardiovascular type of workout. Your goal is to progess to the faster pace for longer and longer periods while decreasing your slower pace to make the interval look more like 2 minutes at the faster pace and 1 minute at the slower pace. This can be done with any type of aerobic workout that I mentioned above.
2. Cross train. This is really important. If you do the same workout over and over again negative things can happen. 1. You can injure yourself due to overtraining (doing the same thing over and over again will take it's toll on you and your muscles)--trust me, I know about this one. 2. You can stop progressing--meaning that if you do the same thing over and over again, your body and your brain know what to expect--you will plateau in both weight loss and endurance. So pick a completely different workout to do and alternate it with what you are doing now--take up a sport, take a different type of class, do some strength training.
3. Circuit train. This is the type of workout that I prefer to do. It mixes aerobic exercises and strength training exercises to get a total body workout. This type of workout can be done by setting a timer and doing an exercise for that specific amount of time and then moving onto another exercise for the same amount of time, or it can be done by counting repetitions--10 pushups followed by 20 jumping jacks, etc. Because these exercises are done for short periods of time--usually not more than a minute, you can work out at a higher intensity and that is going to burn more calories.
Even though this is my preferred way to train, I still cross train by going on hikes or bike rides, or doing yoga to keep my body as healthy as possible.
Next--Strength Training 101