Health and illness are different terms, and my definitions are reflective that they are two coexisting elements of the human condition. Health I think of as a spectrum or 1-10 scale. A 10 would be someone who is free of chronic illnesses such as diabetes, cancer, etc and who lives a lifestyle low in risk factors for chronic disease (regular exercise, balanced diet, no smoking or heavy alcohol use). Illness I define as any dysfunction in normal body function.
I think my definitions of health has origins in personal experience and seeing how others treat their bodies. Everybody has heard an anecdote along the lines of “my uncle smoked two packs a day and lived till 80 until he got hit by a truck!” but I wouldn’t describe such a person as being in good health. Personally, I feel that I’m a pretty healthy person because I watch what I eat and run long distance 5-7 days a week. However I know that sometimes people get too drunk and order two meals from Taco Bell in a night. An occasional episode of unhealthy behavior doesn’t make someone unhealthy – much like having an acute disease such as a cold. It is once these bad choices become habit when it starts to resemble chronic disease, and thus leads to a drastic deterioration in health.
Sadness in an emotion that just about everyone will feel in their lifetime. Some people feel it more often than others and sometimes it can linger for a long time. It is a natural emotional response that can be evoked by the loss of a hockey game or the ending of a long term relationship. However, it can become an illness – namely depression – if it persists for a long time and reduces the individual’s capacity to function normally. Depression can lead to a severe loss of productivity, disinterest in seeking pleasure and suicide. Once it crosses that line into depression, sadness is an illness.
Cancer is most definitely an illness by my definition. Biologically it is uncontrolled growth in the body, a dysfunction in replication and many other pathways. Relating to the broader definition of illness as contrasted with “disease”, cancer takes over one’s life. The treatment is very demanding and strong social support can make a huge difference in the patient’s recovery.