May 2001

Physical Fitness

Jim Verners DC, FCCSS(C)

Simply put, Physical fitness is the ability to perform the demands of an active lifestyle without getting too tired. However you cannot be fit without being physically active. No matter how active you once were, your present fitness depends on the physical activities you are doing now.

Physical fitness includes several components including:

1. Body Fat and Composition: The body is composed of two types of tissue: fat and lean body tissue (muscle, bone). The frequently used height-weight tables are of limited value in the evaluation of body composition and may give a false impression.
2. Flexibility: Flexibility refers to the range of movement of joints. Improving flexibility usually involves stretching muscles by either slow static stretches, which you hold for 10 to 30 seconds, or stretch with some movement (shoulder).
3. Muscular Strength and Endurance: In order to increase strength and endurance, the overload principle of exercise must be used. In order to produce strength gains, progressively increase the exercise weight and to produce gains in endurance increase the number of repetitions gradually.
4. Cardio-Respiratory Fitness: Cardio-respiratory fitness refers to the combined efficiency of the respiratory system in taking in oxygen, the circulatory system in delivering the oxygen to the muscles and then the utilization of the oxygen by the muscles to produce energy.

Exercising effectively and safely involves keeping your heart rate within the target zone as you exercise. The desired range for heart rate during exercise differs according to age, but regardless of age, exercise must be maintained with the given heart rate for 15 minutes, three to four sessions per week in order to achieve and maintain fitness.

Your Exercise Training Program
Every exercise session should begin slowly with a warm-up period. This allows your muscles, joints and cardiovascular system to become accustomed to the increased activity. The next phase of a training program involves a stretching program to improve and maintain your flexibility.

The crucial part of the workout is the duration one stays within the target heart rate zone. Often a good way to tell if you are overexerting is whether you are to breathless to carry on a conversation comfortably while exercising. If you are, slow down. After you have spent time in the target heart rate zone you should go through a period of "cooling down," gradually reducing your activity level. Cooling down allows the body to adjust as you stop exercising. If you stop abruptly, blood can be trapped in the muscles causing a sudden drop in blood pressure and possibly dizziness or fainting.

Making Progress
As you start in your exercise program you may find that even very moderate activity will produce your target heart rate, but as you become more fit increasing amounts of activity will be required before the target rate is achieved. Use the FIT formula to get the right amount of exercise;

Frequency: train at least three times a week
Intensity: work hard enough that you increase your heart rate into your training range
Time: fifteen minutes of activity brisk enough to keep your heart in the training range
Type: activities that keep you moving continuously such as bicycling, jogging, swimming, walking.

The Last Word
Although physical fitness can be achieved by doing the right kinds of physical activity, it also depends on sound eating habits and proper rest.