It's impossible to envision the second half of life without thinking about your health, especially your risk of developing debilitating or life-threatening diseases in the future. Your health risks as a woman are, for the most part, a result of your genes, your habits, and your age.
Your genes. Although you can't exchange the genes you inherited, you can, increasingly, use the information they contain to develop your health strategy. Family history, especially when close relatives develop a disease early in life, can indicate an increased risk. Genetic testing, which is available for some forms of breast cancer and some other inherited disorders, can give a more precise indication of risk.
Your habits. Smoking, sun exposure, alcohol consumption, diet, and physical activity also play a major role in determining your disease risk. While you can't entirely undo the effects of past practices, you can arrest, and even reverse, much of the damage.
Your age. Aging -- the result of gradual physical changes that occur naturally over time -- is caused in large part by cell damage and cell loss. The damage may be inflicted from outside the body, for example by toxic chemicals or radiation. It can also be a consequence of normal body processes, like metabolism, that produce harmful oxygen-free radicals. Mistakes can also occur when DNA is copied during cell division. Although the body has systems to to fix various types of cell damage, the repairs aren't always complete, and as the years pass, the damage accumulates.
Moreover, even undamaged cells aren't immortal. Each cell has a predetermined lifespan, which varies by tissue type. With age, cell numbers decline as cell death outpaces cell division. As the number of undamaged body cells diminishes, bodily functions -- including digestion and metabolism -- slow. It takes longer for nerves to respond to stimuli. Hormone levels fall as endocrine gland function declines. That said, however, the effects of aging vary significantly among body systems and from woman to woman.