What is health?

I am currently taking a Health Psychology course. Most people I mention this to respond immediately with "What's that?"

This question begets another: "What is health?" The definition of health has changed considerably in the past century. In the early 1900's, health was though of as the absence of disease. This is because the diseases that were most common at that time were largely the result of contact with impure drinking water, contaminated foods, or sick people. The leading causes of death were from infectious diseases (typhoid fever, pneumonia, diptheria, influenza, tuberculosis). The afflicted either died or got well in a matter of weeks.

But during the 20th century, health changed in the U.S. - the leading causes of death changed from infectious diseases to chronic diseases such as heart disease, cancer, stroke, chronic lower respiratory diseases such as emphysema and bronchitis - all of which relate to individual behaviors and lifestyles. These diseases were not new, but the proportion of people who die from them changed. We found out how to deal with the infectious diseases and started living long enough to die of chronic diseases, which can be tied to smoking, alcohol abuse, unwise eating, stress, and sedentary lifestyle. Robert Sapolski (1998) said "We are now living long enough to slowly fall apart." Indeed, in the 20th century life expectancy increased by 30 years, thus leaving us exposed to death from diseases that 100 years ago we weren't living long enough to get.

Although chronic diseases have many causes, individual behavior and lifestyle have an enormous impact on their development. Because behavior is so important for chronic disease, psychology, which is the science of behavior, has become involved in health care. A large part of psychology's involvement in health care is a commitment to keeping people healthy, rather than waiting until after they are ill to treat them. Unlike medicine, psychology contributes to broad principles of behavior which directly impacts health issues and diseases. Why do people exercise... or why don't they? Why do people try to eat a healthy diet - or why don't they? Why do people smoke? Why can't they stop? Why to people engage in such unhealthy behaviors, and what would it take to change these behaviors? Why do people seek medical care, and at what point? Why do they fail to seek medical care? What would it take to change this behavior? How are these behaviors influenced by ethnicity, education level, income level, and age?

These are the concerns of Health Psychology.

Health is no longer defined as the absence of disease. In 1946 the World Health Organization (WHO) wrote the modern Western definition of health: "Health is a state of complete physical, mental, and social well-being, and not merely the absence of disease or infirmity.", which affirms that health is a positive state and not just the absence of disease. Feeling good is more than just not feeling bad.