Alphonso Evans rolls his wheelchair into a weight machine in the gym at the Charlie Norwood VA Medical Center in Augusta, Ga.
"I'm not so much worried about dying from a heart attack or diabetes, because I'm active. I know what to do to work against it: watch what I eat, exercise," Evans says. "But what do I do about an infection? Or fighting off a bacteria — something inside me that I don't see until it's too late?"