The definition of aerobic activity is quite broad, giving you a variety of fat-burning opportunities and virtually destroying the fear of boredom. Sure, everyone has jogged, stair-stepped, biked and walked, but how about swimming, rowing, cross-country skiing, jumping rope or in-line skating? To be aerobic, an exercise must simply be continuous (generally for at least 15-20 minutes), rhythmical and involve the larger muscles of your body. This results in oxygen being used to predominantly break down fat for fuel, making aerobic exercise a more effective fat-burner than bodybuilding alone. Naturally, using bodyfat for fuel will lower your percentage of bodyfat, making you leaner. Other benefits of aerobic (or cardiovascular) work include prevention of heart disease and developing your slow-twitch muscle fibers. As you develop these endurance fibers, you'll note more endurance in your workouts, which could lead to longer, more intense iron sessions. Just as you have an extensive number of exercise choices, you have several ways you can go about doing them. For example, exercising for long periods at a low intensity used to be the main recommendation for bodyfat loss. This approach isn't the best way to accomplish the goal, however, because the low intensity doesn't burn very many calories. Yet it can be effective for improving cardiovascular health. Exercising for shorter periods at high intensity, on the other hand, will burn more calories. While this may be the most effective in terms of calories used per minute, this approach is very taxing and requires a high degree of conditioning.

The difference between aerobic and anaerobic training

Running, cycling and swimming are aerobic activities; weightlifting, sprinting and boxing are not. During aerobic exercise, the heart rate rises, respiration increases and carbohydrates and fats provide working muscles with energy via oxidation. During anaerobic activity, the heart rate and respiration increase to a greater degree, but stored adenosine triphosphate (ATP) and creatine phosphate serve as primary energy sources. As a result, lactic acid accumulates in the muscles and blood. Another way to understand the difference between aerobic and anaerobic work is to think in terms of duration and intensity. If you can do an activity for a relatively long time (at least 20 minutes), the intensity will have to be light to moderate so that you can keep it up. This is considered aerobic. Exercising at a high intensity - so high that you can't continue at that pace for more than a minute or two at a time - is anaerobic. But no exercise or activity is 100% aerobic or anaerobic. Sprinting may be anaerobic, while marathon running is aerobic, but when long-distance runners sprint for the finish line, they're activating their anaerobic metabolism

Heart and health benefits

Aerobic activity offers a wide variety of benefits to overall fitness and health. The visual improvements are great, but the long term, more important advantages occur on the inside. Together with cardiovascular efficiency, metabolic changes will take you another step closer to achieving ultimate fitness. You know aerobic exercise causes your body to burn calories, a percentage of which come from fat, depending upon (among other things) duration and intensity. But did you know that you continue to burn fat even after your workout is over? After training, the body needs to replenish muscle glycogen, and fatty acids help to manufacture ATP. Basically, fat is used to partially refuel the body for its next burst of energy. The more intense the exercise, the more the body has to replenish, and the more fat it will use to do just that. Now as far your heart goes, aerobic exercise lowers your resting heart rate, increases stroke volume and improves the efficiency of the heart. A trained heart doesn't have to work as hard to deliver blood to the various parts of the body and can pump more blood with each beat than an untrained one. Aerobic training can also lower blood pressure, which in turn decreases the risk of heart attack.

Determining the intensity of your cardio sessions

Fast-paced running (approximately 80%-90% max heart rate):
Burns more total calories and fat calories per minute than less-intense running.
Advanced-level fitness.

Medium-paced running/jogging (approximately 70%-80% max heart rate):
Burns fewer fat and total calories. Good fitness benefits.

Very fast walking (approximately 60%-70% max heart rate):
Burns a relatively high percentage of calories from fat but few overall calories.
General health/cardio benefits.

Moderate-paced walking (approximately 50%-60% max heart rate):
Burns a high percentage of calories from fat, though few total calories.
Some cardio benefits.

Finding your target heart-rate range

To find your estimated training zone of safe and effective exercise pulse rates, follow this simple formula:

Taking your pulse

Rate of perceived exertion (RPE)

Heart-rate monitors