This question has been asked and answered by a lot of people over the past several centuries. Some equate fitness with health, others with athletic ability. Alhough fitness can mitigate a lot of health problems, it doesn't automatically equal health. Genetics dictate a lot of what happens to us and there's no treadmill or barbell that can change what's in your genes. Likewise, we can't really do much about the things we encounter in our daily environment that may impact our health over decades of exposure to things we aren't even aware of. However, that being said, one can't simply ignore the benefits of fitness on one's overall health, especially in our current American epidemic of obesity, diabetes, high blood pressure, and heart disease. According to the International Sports Sciences Association, founded by Fred Hatfield and Sal Arria, "it is difficult to separate health and performance related physical fitness. Certainly, they overlap. For simplicity, health related fitness components include cardiovascular endurance, strength, flexibility, and body composition. Performance related fitness includes all of the above along with power, agility, speed and balance."