Distinguish among physical fitness, cardio respiratory fitness, and metabolic fitness.

Physical fitness is the ability to respond to routine physical demands, with enough reserve energy to cope with a sudden challenge. You can consider yourself physically fit if you meet your daily energy needs, can handle unexpected extra demands, and re protecting yourself against potential
health problems, such as heart disease.

One component of physical fitness is cardio respiratory fitness, which refers to the ability of the heart to pump blood through the body efficiently. Cardio respiratory fitness is achieved through aerobic exerciseany activity, such as brisk walking or swimming, in which sufficient or excess oxygen is continually supplied to the body. In other words, aerobic exercise involves working out strenuously without pushing to the point of breathlessness.

Metabolic fitness is also a component of physical fitness. Metabolic fitness, which is linked to a reduced risk for diabetes and cardiovascular disease, can be achieved through a moderate-intensity
exercise program even with little or no improvement in cardiorespiratory fitness.