If you select "Keep me signed in on this computer", every time you visit WebMD.com you won't have to type your email address and password. This means that a cookie will stay on your computer even when you exit or close your browser which may reduce your levels of privacy and security. You should never select this option if you're using a publicly accessible computer, or if you're sharing a computer with others. Even if you select this option there are some features of our site that still require you to log in for privacy reasons. "For every one person who lives a long life of unhealthy choices, there are countless others who die prematurely because of them," says Robert Schreiber, MD, physician-in-chief at Hebrew SeniorLife, an elder health care provider and affiliate of Harvard Medical School. Betting that you will be one of these people is playing a game of Russian roulette, Schreiber says. The seeds for illness in many of Schreiber's patients in their 70s and 80s were sown in their 30s, 40s, and 50s, he says. "Probably 50% of cases of the most serious conditions -- heart disease, diabetes, stroke, many forms of cancer -- are related directly to lifestyle and behavior," Schreiber tells WebMD. No one is guaranteed a life free of disease or injury. As we age, many of us will face at least one of these common health problems. But certain lifestyle steps can help forestall illness and sometimes prevent it altogether. They can