Physical activity is necessary to stimulate the body's own natural maintenance and repair system.
Your bones, joints and muscles - especially your heart - will actually stay younger if you keep them busy.
If you are not physically active you are more likely to suffer from heart disease, strokes, high blood pressure, breathlessness, a flabby body, low energy levels, stiff joints, bone problems, poor posture and being overweight.
The three main components of being physically fit are stamina, strength and suppleness.
With stamina you have a slower more powerful heartbeat and will be able to keep going without gasping for breath.
Strength comes from having well-toned muscles. When your shoulder, trunk and thigh muscles are toned-up you will not experience strains and injuries as often.
Developing suppleness or flexibility in the muscles in your neck, spine and joints will prevent sprains or pulled muscles and tendons. You will also be less likely to experience aches and pains from stiff joints.