Physical fitness is an inclusive term that encompasses a variety of factors that are important in promoting health. Physical fitness refers to the ability to do various parts of daily tasks, occupations, and sports and, in general, a state of good health. This state is achieved by meeting the body’s basic requirements such as obtaining sufficient sleep and nutrients, for healthy processing of energy. The term physical fitness should not be confused with healthy weight, though they are often interrelated and even dependent upon one another. Weight loss can improve one’s physical fitness level but the improvement is only temporary and not a guarantee that the person will maintain the improved weight once he or she has lost it.
To understand how fitness means good health, it is important to recognize what fitness really is and how it differs from the concept of “exercise.” Exercise refers to the systematic and rationalized use of muscular strength and movement in order to accomplish an objective, such as moving from point A to point B. Fitness therefore implies a correspondence between the objective and the means used to meet it, and between the degree of exertion and the degree of danger or discomfort connected with exercise.
Fitness also requires that the participants in the physical activity engage both the active and passive muscles of the body. An individual who exercises is capable of producing a force (motion) that acts in a direction independent of his own motion. Hence, muscular strength and flexibility are not exclusively related to muscle size and strength but also involve the extent of motion, particularly the power involved in performing the activity. Flexibility, in fact, is only one of the many essential components of fitness.
Another aspect of fitness relates to cardiac output and pulmonary efficiency. Cardiovascular fitness refers to the ability of the heart and lungs to pump blood efficiently throughout the body. Individuals who are physically fit have well-developed heart rhythms with normal or low cardiac workload. They have high pulmonary efficiency, which is the efficiency of the pumping of air in and out of the lungs for providing oxygen to the body. Individuals who are physically fit also have high levels of energy, both through muscular strength and cardiovascular capacity.
The concept of “fitness” is most closely linked to the concepts of body shape and composition. An individual’s shape and composition are primarily influenced by genetic factors. Nevertheless, even individuals who possess the same genetic composition can exhibit very different levels of physical fitness. In view of this, many individuals who possess very similar physiques are said to be in the same fitness group, regardless of muscle mass or muscle fiber type. This suggests that muscle size and strength do not necessarily lead to overall fitness levels.
In order to obtain a full understanding of fitness, an individual must have some understanding of the meaning of terms like “endurance,” “fatigue,” and “power.” Endurance describes the capacity of a person’s energy supply, while fatigue and power represent the ability of the body to function for a period of time. “Power” is what distinguishes athletes from sedentary people, as well as the healthy from those that are physically unhealthy. As the name indicates, fat constitutes the majority of a person’s mass. Therefore, fitness mainly depends on how much fat a person has versus the muscle mass they possess. Finally, the term “fitness” can also refer to the level of flexibility one’s body exhibits.