Lately, walking has become the exercise of choice for millions of Americans trying to get and stay fit. Throughout the U.S., walkers attired in various styles of workout apparel, many wearing fanny packs around their waists, can be seen daily dotting the landscape as they energetically move back and forth.

When compared with that other popular aerobic exercise, jogging, walking causes less shock to the lower back, the hips, the knees, the ankles and the feet. The force of jogging can subject joints to impacts three to five times a person's body weight each step. With walking, however, one foot always remains on the ground, thus the shifting of body weight is more fluid. For this reason, a walker lands with only one to one point five times the force of his body weight each step.

True, walking does take a mite longer to do than jogging. But you can burn nearly as many calories (e.g., walking at a 15-minute-a-mile pace you can burn approximately 100 calories per mile, whereas jogging at a 10-minute-a-mile pace you burn roughly 20 calories more) and get nearly as good a workout by walking that mile as you can by jogging, bicycling or swimming at a moderate pace. The heart doesn't make a distinction between any of these activities; its job is solely to deliver the blood and oxygen needed to the working muscles.

The heart muscle, like all the other muscles of one's frame, needs to be challenged with exercise to keep it strong enough to receive and pump blood through the arteries and veins to the rest of the body. A heart that has developed strength and endurance through an aerobic undertaking such as walking has not only a lower resting and working rate of speed (i.e., performs its function using fewer beats) but also sends out more blood with each beat.

Moreover, walking enables a person to see the world in which he or she lives in greater detail. Scenery such as buildings, houses, trees, flowers and lawns become more noticeable when one is on a walk.

Walking also frees the mind for creative thought. Many walkers possess a belief similar to that of Henry David Thoreau, who once said, "Methinks that the moment my legs begin to move, my thoughts begin to flow." Akin to Thoreau, these walkers state that they do their most productive thinking while walking and are better able to solve complex problems.

Nevertheless, although walking is a low-impact exercise that's less strenuous and less harmful than jogging, beginning walkers still should pay attention to taking those precautionary measures that will help protect them from injury.

In particular, along with putting on comfortable, unbinding clothes, they should wear lightweight, properly fitting walking shoes with enough support and cushioning in the heel and arch to minimize the pressure on their joints; being mindful of the calf muscles as well as the muscles at the front and the back of the thighs, they should do about 10 minutes of warm-up exercises and 10 minutes of cool-down exercises consisting of static (no bouncing) stretches – holding each stretch for 20 to 30 seconds, before and after walking to prevent damage to their muscles and tendons; and, they should attempt to walk on a flat cushioned surface to reduce the strain on their legs and feet. By following these precautionary measures, beginning walkers are less likely to get injured and require days or weeks of non-participation in exercise in order to recuperate.

Concerning form and technique, it's best when walking to keep the body erect, the head up, the eyes looking straight ahead, the shoulders down, the buttocks tucked in and the arms at waist level. Specifically, you should bend the arms at the elbows (at a right angle), with the elbows held out a bit from the sides and the arms pumping alternately from front to back with the stride. Try not to swing the hips from side to side as you walk. Each foot should land under the torso, almost flat and toward the heel. A short, heel-toe stride is recommended for walking by most authorities.

Perhaps more importantly, your walking pace should be one in which you are able to talk without becoming winded, without panting and gasping for air. This especially applies to those people just getting back into exercise after a two or three decades lay off.

Walking is so natural, so automatic that a lot of people tend to overlook its potential as exercise. One can walk at a brisk stroll, a rapid gait, or anywhere in between. Any of these speeds can aid walkers in reaping many of the benefits that come from working out.

To take a single instance, one of these benefits is: a delaying of the aging process. Recent medical research reports that millions of us cease to engage in activities that are physically demanding as we grow older; however, this same study says that involvement in such a rejuvenating activity as exercise can help to preserve our ability to carry out daily chores with relative ease as well as help to stave off the degenerative effects of aging. Even a moderate exercise program that's done on a regular basis can promote better physical and mental health.

The widely held belief that exercising has to be a painful endeavor in order to create a favorable outcome is false. In reality, being consistent and persistent are much more essential to making beneficial improvements than how much pain you can endure during a workout.

Although, at the outset the body may rebel against your attempts to whip it into shape and leave you tired, stiff and sore after workouts. But this unpleasant fact of exercising is tempered by realizing that these minor discomforts are temporary. Once you become accustomed to working out regularly, exercising vigorously will be easier to do, and the minor discomforts will all but cease to exist.

Now, in reference to world-class Olympic athletes trying to achieve their lofty objectives of winning gold medals and other awards, learning to push themselves beyond the manifold barriers that stand in the way of victory is a relevant concept. But it's an immaterial concept with regard to normal body conditioning. Besides feeling and looking great, here, one's focus is on sound internal health, physical strength and a long, productive life.

All the same, even though walking at a tortoise-like pace will get you from point A to point B without shattering your laid-back image and producing sweat, to elevate your heart rate to a cardiovascular fitness level you're going to have to expend some energy in your walking motion. Yet, with no more than a spirited arm swing and an accelerated stride, you can attain a significantly higher heart rate.

In fact, to make a walking program an effective one, many doctors and trainers recommend that walkers walk for at least 30-minutes a minimum of three times a week while maintaining a certain target heart rate.

However, if your heart rate overly exceeds the pre-determined target heart rate, it could mean that too much stress is being placed on the body. Conversely, if your heart rate falls well below the pre-determined target heart rate, your pace won't be sufficient for a good aerobic workout. Consequently, it is very important that walkers are knowledgeable about and are able to correctly estimate their exercising heart rates.

A simple way to figure out your target heart rate is to take the number 220 and subtract your age. The remainder represents your maximum heart rate. Your goal now is to begin exercising at some percentage of this number. Typically, for people who haven't taken part in vigorous exercise for a while, the percentage of your maximum heart rate will be around 55 to 65 percent; and for people who are hale and hearty, the percentage of your maximum heart rate will be around 70 to 80 percent.

As an example, if you're 40 years old, you would subtract that from 220 and find your maximum heart rate is 180. Assuming you're one of the hale and hearty people, you would then multiply 180 by .70 and get 126.00. Thus, you should be walking at a pace that will cause your heart to beat at a rate of 125 to 135 beats a minute.

For a person having difficulty taking his or her exercising heart rate, the easiest places to count it are the radial artery on the wrist and the carotid artery on the side of the neck. Use the first and second fingers of the hand and place them on the thumb side of your wrist or place these same two fingers on the opposite side of your neck. Take your pulse for 15 seconds, then multiply by four.

After successfully completing at least eight weeks of diligent, progressively vigorous, injury-free walking, you may now consider making your training regimen a little tougher.

Through walking, you have made your leg muscles stronger, yet to this point your upper body has been virtually ignored. By carrying one to five pound hand weights while walking, you will not only tone up your arms but heighten the intensity of your workout as well. Furthermore, walking up and down hills, walking in sand at the beach, and ascending and descending flights of stairs are some other ways to challenge and strengthen the muscles of the feet and legs as well as the heart and lungs. Additionally, you will be pleased to know that by increasing your efforts you'll also be able to burn up more of those fat grams that produce a large number of calories and, as a result, extra body weight.

Later on, when you've become really fit, "speed walking" (i.e., walking at a 12-minute-a-mile pace) can be the next mountain to climb in your ambulatory adventure. Though speed walkers may look peculiar as they move, speed-walking is actually a much greater challenge than jogging at the same speed because the muscles must work harder to hold the fast-walking pace without breaking into a jog.

Nonetheless, since one's target heart rate and the duration and intensity of a walking program varies according to age, weight, hereditary background and other factors, you first should go to a medical professional for a checkup and more detailed information regarding the most appropriate walking program for you.