Aerobic exercise has lower intensity and is performed for longer time periods. Examples: Using the stationary bike for 40 minutes, jogging for 30 mins - even doing the "chores" around the house.

Anaerobic exercise is higher in intensity and lower in duration. For example, sprinting for 150 yards, lifting a weight for 10 reps (and not being able to lift it more times) etc...

Which is the best type of exercise? You can use both if you want - but if I had to choose one type, I would go with ANaerobic. This means resistance training and weight lifting. Doctors have "prescribed" aerobic training over anaerobic for years - mainly because they have no clue about strength training. If you don't believe me, look at your doctor and see how out of shape he is.

People who say "I'm doing aerobics because I want to have a strong heart" have obviously never done any weight training. If you tell them to do a few sets of "squats" with the maximum weight they can handle for 10 repetitions (reps), they will almost have a heart attack. Hey, I thought that weight training doesn't work the heart (surprise, surprise).

Weight training is great and is actually EASIER to start with than aerobics. The exercises are usually "non-impact" and don't hurt your joints (something that doesn't happen when you jog on the road for example). Plus, each exercise can be preformed with 10 pounds or less all the way up to 2000 pounds and more. No matter what level you are at, you can do weight training.

Most people have a subconscious fear of lifting weights. This activity is connected in their minds with images of extreme distress and agony. It doesn't have to be that way. Again, start by lifting only 2 pounds if need be. If you can't even lift 2 pounds (a task most 5-year-olds do routinely) then you are in for a world of hurt in every day life. Also, there's no reason to "push it" until you are out of breath and shaking all over. Take it easy. Start slowly and work up from there. This isn't a contest to see who can suffer more.

Weight training has two distinct advantages over aerobics:

1) It builds muscle witch makes you stronger and sexier. Building muscle requires a tremendous amount of energy from the body. Where do you think it will get the energy from? Right: From your fat deposits around your thighs and midsection.

2) It burns MORE fat than aerobics. Most of the fat burned when doing weight training is burned AFTER the training session has finished. Your metabolism will be higher for several hours after you finish training.

If you don't believe me that weight training rules, just look at the two ends of the spectrum: Marathon runners and sprinters. Marathon runners train aerobically running for many miles. Sprinters do an "all out" sprint for 100-400 meters - the sprint finishes in a few seconds. Both of these athletes have low bodyfat levels. But marathon runners look like they escaped from a concentration camp - while sprinters have well-developed muscles and look powerful.

Be practical. If you are going to exercise, at least do it in a manner that will make you more functional in your every day life. Most of us will need to pick up a heavy object, pick up a child, run to catch the bus etc. These are real-life circumstances that will require strength.

When was the last time you had to walk for 5 miles or do something "aerobicish" for 60 minutes? I don't know if the need to do that appeared in my life even once. Most "real life" tasks require strength - not endurance for hours...