The most widely accepted definition of health is that of the World Health Organization Constitution. It states: "health is a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity" (World Health Organization, 1946). In more recent years, this statement has been amplified to include the ability to lead a "socially and economically productive life". The WHO definition is not without criticism, mainly that it is too broad. Some argue that health cannot be defined as a state at all, but must be seen as a dynamic process of continuous adjustment to the changing demands of living. In spite of its limitations, the concept of health as defined by WHO is broad and positive in its implications, in that it sets out a high standard for positive health.

The most solid aspects of wellness that fit firmly in the realm of medicine are the environmental health, nutrition, disease prevention, and public health matters that can be investigated and assist in measuring well-being.

General fitness :-

In its most general meaning, physical fitness is a general state of good physical health. A physically handicapped person's body may be physically fit (healthy), though its ability is likely to be less than optimum.

Physical fitness is usually a result of regular physical activity and proper nutrition.

Physical fitness can be divided into different areas, including:

 Flexibility, Cardio-respiratory endurance, Strength

The government Physical Activity Guidelines for Americans say to aim for at least 2 hours and 30 minutes of aerobic activity that requires moderate effort each week.

Task-oriented fitness:-

A person may be said to be physically fit to perform a particular task with a reasonable efficiency, for example, fit for military service.

Military-style :-

In recent years, Military-style fitness training programs have become increasingly popular among civilians. Courses are available all over the United States and Europe.

These courses always have some common elements. They often focus on military style calisthenics and group runs. The courses are often held very early in the morning and will meet in almost any weather. Students can expect push-ups, sit-ups, pullups, and jumping jacks, as well as more obscure drills such as flutter kicks, sun worshippers and flares. Almost invariably a workout will include short runs while longer runs are more scheduled. Special forces are commonly renowned for their level of fitness and intensity of their workouts.

A healthy diet is a diet which contains a balanced amount of nutrients, varied food such as fruits and vegetables, proteins primarily from fish, dairy products, and nuts. Minimal amounts of caffeine, sugar, fat, salt, and alcohol. Healthy eating is identical to a healthy diet, in that it relates to the practice of food intake for healthy living. Governments often use this term to refer to the ideal diet which the average person requires to remain healthy...