Health, as defined by the World Health Organization, is a condition that is characterized by a level of healthyness that is maintained through bodily processes, and the absence of diseases and other infirmities. A number of definitions have also been applied to health since time immemorial. In traditional societies, health was seen as a spiritual and mental state and was closely associated with behavior. In modern times, health has become a largely technological phenomenon with the advent of medication, nutrition, healthcare services and hygiene. With the increase in levels of stress, pollution, depression, anxiety, high-fat diet, sedentary lifestyle, aging and other diseases, people have begun to perceive health differently.
The concept of health is now associated with both physiological and behavioral aspects. Physiological aspects include measures of body composition, blood pressure and pulse rate, weight, and body fat. These measurements are essential to establish the basic health status of an individual, but more importantly, they are tools for determining risk factors, defining healthy practices and developing preventive care plans. The emphasis on individual behavior, which includes proper diet and physical activity, has also become an important component of public health.
A public health program is concerned with the overall well being of an individual and the society at large. It attempts to reduce the burden of mortality, to promote healthy living through a balanced system of prevention, assessment and treatment, and to preserve the community, culture and economy. Prevention programs involve promoting healthy behaviors through education, research, policy and practice. Programs that address environmental factors include creating a healthy environment through environmental assessment and management, promoting healthy spaces through active involvement, and preventing or reducing traumatic health outcomes through support for the vulnerable.