There are two key components to your exercise regimen - aerobic exercise and anaerobic exercise.

Aerobic Exercise

Flashback to the 1980's when girls wore spandex and leg warmers to the local club to bounce around to upbeat music by big-haired bands.  Aerobics, right?

Wrong, thank goodness!

Aerobic exercise, also commonly called cardio, is simply exercise that induces a high rate of oxygen consumption in the body.  Aerobic exercise can include such activities as brisk walking (treadmill or outdoors), stair climbing, cross-country skiing, running, aerobics classes, kickboxing, or riding a bicycle.  Performing aerobic exercise should induce a state of heavy breathing (without gasping) such that more oxygen enters the body for use by the muscles.  The heart rate should be accelerated but not racing.

The nice thing about aerobic exercise is the fact that there are so many ways to go about doing it.  Boredom should never be a factor in aerobic activity.  Don't feel like running?  Jump on the elliptical or stair climber.  Raining outside?  No excuse - do jumping jacks indoors.  So many options!

Ideally, cardio should involve a short warm-up period followed by a period of intense movement. 20 to 30 minutes of intensity should suffice.  At the end of the workout, a period of cool down will allow your body to gradually return to a semi-rested state.

Delving further into the aerobic aspect of exercise, we find that cardio can include both high intensity intervals and endurance training.  High intensity interval training (HIIT for short) is a method of aerobic exercise wherein the participant follows a period of low intensity exercise with a period of high intensity exercise.  The pattern is repeated multiple times for anywhere from 5 to 30 minutes.  For example, if the participant is running, she might start at a brisk walking pace for two minutes to warm up.  The warm-up period is followed by a 1 minute jog.  At the end of the jog, the participant performs a 30 second sprint.  The jog/sprint combination is repeated for as long as fitness will allow.  Less fit individuals might find that 5 minutes of such activity is all they can manage, while more fit participants will repeat the pattern (with longer intervals) for up to 30 minutes.  As always, a 3-5 minute cool-down period should follow the HIIT in order to allow the heart rate to slow and breathing to resume a normal pace.

Endurance training is different in that the participant performs the exercise at a consistent or near-consistent pace for an extended period of time.  The exercise might include a 2 minute warm up followed by a 40 minute run with a 3 minute cool-down period.  There are no periods of high intesity, rather the level of intensity remains fairly constant during the main phase of the workout.

Both forms of aerobic exercise, HIIT and endurance training, are effective for burning fat.  However, certain practices can accelerate the fat-burning potential of aerobic exercise.  Specifically, performing the aerobic exercise on an empty stomach (first thing in the morning or no earlier than 3 hours after eating) and then waiting 30-60 minutes to eat after exercising can potentially burn more fat.  The lack of food preceding and following the exercise forces the body to seek out available fat stores for energy.

If your goal is to drop fat, aerobic activity will be necessary part of your exercise regimen.

Anaerobic Exercise

Aerobic exercise is a high-oxygen program; ANaerobic is its opposite.  The key to anaerobic exercise is training the muscles by use of weights or another form of resistance (resistance bands, isometrics, etc.).  High oxygen intake isn't necessary, thus making the exercise anaerobic - without oxygen.

Weight training can be broken down into the various body parts: calves, front thighs (quads), back thighs (hamstrings), abdominals, shoulders, back, chest, triceps (back of the upper arm), and biceps (front of the upper arm).  The ways in which these various body parts can be trained are far too varied for me to cover in this article.  Perhaps the best plan for the novice is to find a capable and knowledgeable personal trainer that can not only design a training regimen for you but will also teach varieties of exercises that will train the different muscle groups.

If hiring a personal trainer is a little out of your price range, then you can find numerous books and other resources that can teach you the ins and outs of weight training.  The Amazon link to the right might get you started down that path.  If joining a gym is also out of your budget, then the Men's Health book (again, to the right) has a wide variety of exercises that can be performed in your home without any weights.  You might also purchase a fairly inexpensive resistance band that will allow you to do resistance training without having to invest a lot of cash.

A big benefit of anaerobic exercise (besides the great look of properly developed muscles) is that the muscle tissue burns more calories at rest.  Even when you're not in the gym, your body will be busily burning calories to support all the new muscle mass that you are developing in the gym.

Muscle recovery is a very important aspect of weight training.  Eating a small meal about an hour before training will provide necessary energy and fuel for the muscles during the workout.  During the workout, consuming occasional sips of a protein-rich shake will provide immediate recovery material to the muscles.  Finally, after your weight training session has ended, immediately consume a protein source that can be quickly absorbed (whey protein shake) in addition to a sugar-rich drink of some sort (a sugar-rich sports drink such as Gatorade is good).  The sugar in the sports drink will do two important things: it will suppress cortisol, which was released during your weight training session, and it will spike insulin enabling the protein from the shake to get to the muscles more efficiently.

Putting It All Together

In order to truly transform the body, both aerobic and anaerobic exercise should be employed.  If your primary goal is to drop a lot of fat weight, then the emphasis should be placed on the aerobic aspect of exercise with weight training taking up only 2 days of your schedule.  If your goal is to merely drop the last 10 pounds or so of fat, then a balance of 3 days aerobic and 3 days anaerobic will be the best fit.  If you find yourself reading this article as a lean machine looking to add muscle, then your emphasis will be on weight training (and eating a lot of CLEAN calories) with only 1-2 days of aerobic exercise.

For the women in the audience, weight training is an integral part of a fat reduction program.  Many times I'll hear women say, "But I don't want to get all bulky."  Under normal circumstances, women who train with weights do not develop super-muscular physiques.  They develop lean muscle tissue without the bulk.  Trust me when I tell you that you will NOT end up looking like the women you see in professional bodybuilding contests.

A simple regimen for someone trying to drop a lot of fat (20 lbs or more) would look like this:

Monday - Upper body workout (Chest, back, shoulders, arms).  Morning endurance cardio optional.
Tuesday - Morning HIIT
Wednesday - Morning endurance training
Thursday - Lower body workout (Quads, hamstrings, calves, abs)
Friday - Morning HIIT
Saturday - Morning endurance training
Sunday - no exercise

That last day off is an important one.  At least one day a week you need to provide your body the opportunity to recover from a week's worth of workouts.  As counter-productive as a day with no exercise might seem, if you fail to give the body the opportunity to recover then you run the risk of burning out.  Once that happens, the body will refuse to give up fat.  Rest on the 7th day.

On a final note, with the amount of exercise that's being performed with the above routine, a decent amount of sleep is mandatory.  The optimal amount would be about 9 hours.  8 is acceptable.  Anything less could sabotage progress by creating too much stress on the body.  Stress has the negative effect of causing the body to retain fat, so we want to avoid any stress outside of the self-induced stress of exercise.

I trust this article has given you at least a sense of direction as you begin the process of transforming your body into a lean, muscular machine.