Physical disabilities associated with chronic disease increase sharply with age, starting with the middle years. While more than half (54 percent) of the 86 million persons who have one or more chronic conditions are under age 45, the prevalence of disability from illness is greatest in the 45 and older age group. Of those under 45 who have chronic conditions, only 14 percent are limited in activity as compared with almost 30 percent of the 45 to 64 age group. And only 1 percent of those under 45 with chronic illness are completely disabled, as compared with 4 percent in the 45 to 64 age group.
These figures suggest that it is wise to have an annual check-up so that any disease process or condition can be nipped in the bud. Regular checkups will not only help prolong life, they will also help you to live it more comfortably.
Here are some other good reasons for having a physical checkup:

If an organ has been attacked by serious disease in youth, it may deteriorate at an early adult age.
Heredity may play an important role in determining the speed of which various organs age. If your parents and grandparents gad arteriosclerosis, there is a chance you might develop this condition in your middle years.
Your environment (smog, poor climate, etc.) might affect the rate at which your body ages, particularly the skin.
Individual stresses and strains or abuses or overuse (of alcohol, for example) may create a health problem in middle age.
The endocrine glands (pituitary, thyroid, parathyroids, adrenals, ovaries, testicles) play important roles in aging. Serious disease of one of more of these glands may lead to premature aging of an organ dependent upon its secretions.
At middle age you are more likely to be beset by emotional strains at work or at home that could make you an early candidate for heart disease, arteriosclerosis, and other degenerative disorders.
The earlier a chronic disease is detected, the better the chance that it can be arrested before permanent damage is done. This is especially true in the case of glaucoma, diabetes, heart disease, cancer of the lung or breast or other cancers?Xall of which could have their onset in middle age.

To help detect disease and other debilitating conditions, many physicians utilize automated medical screening, which combines medical history with selected physiological measurements and laboratory tests to give the physician a complete health profile of the patient. This profile should indicate the probability of any chronic condition, which the physician could then pinpoint with more thorough tests.
Also, annual checkups enable the physician to observe changes taking place over a period of time. For example, he is able to observe gradually changing blood chemistry levels or a progressive increase in eye pressure that could signal the onset of a disease.