Jon Anderson can't run like he used to.
The 66-year-old Vietnam veteran has been running marathons since 1976 and ultra marathons since 2003.
But in 2008, Anderson stopped running, four years after he was diagnosed with Parkinson's disease.
"Probably running one mile would be very difficult for me now," he said.
Anderson said for the past eight years, he saw the disease slowly outrun his body and affecting the way he walks.
"I kind of do more of a shuffle and that's really difficult because you have to will your legs to move," he said. "Just moving your legs normally, you don't think about it you just move your legs from point A to point B . . . but for me, and people with Parkinson's disease it's an arduous process just to walk sometimes."
Anderson said he questioned why he had Parkinson's disease and decided to check with doctors for help.
"I didn't find out anything that linked it at the time," he said.
Anderson said he called the Department of Veteran Affairs and asked what kind of treatment he should undergo following his diagnosis.
The department told him his diagnosis was not considered a service-connected disability, Anderson said.
In 2009, the department announced that veterans with Parkinson's disease who were exposed to Agent Orange during military service may be eligible for disability compensation and health care.
Agent Orange is a herbicide used during the Vietnam War to kill plants in war zones, which made finding hidden enemy soldiers easier.
Although Agent Orange may have been useful in the war, the herbicide is said to be the cause of many health problems for veterans, which includes Parkinson's disease.
"I'm not doing as well now," Anderson said. "So now, I'm developing more of an attitude toward Agent Orange and Parkinson's disease."
Dr. Irene Malaty, a medical doctor from Shands at University of Florida, said the news brings a relief to veterans with the disease.
"In a sense, there's a big victory for those who have Parkinson’s diesease because they no longer have to exactly prove that that exposure caused it, and that it's probable that it did cause it," she said.
See part two of this story here.
Chris Alcantara wrote and edited this story online.