To account for the fact that very sick people can’t exercise, Campbell and his colleagues excluded anyone who died within two years of their last survey, and found similar results. Researchers have known for a while that obesity and exercise affect a person’s risk of getting colon cancer in the first place, said Dr. Jeffrey Meyerhardt from the Dana-Farber Cancer Institute in Boston, who has also studied exercise and colon cancer survival. “The question when you’re a patient with colorectal cancer is, Do those things matter once I get the disease? Are there things I can do in addition to standard treatment to reduce my risk of recurrence?'” he told Reuters Health. Researchers said there are a couple of possible explanations for why exercise, both pre- and post-diagnosis, might benefit people with cancer. “What we think is at least part of what is happening is, people are going into surgery and adjuvant treatment in a more fit state,” Campbell told Reuters Health. In addition, he said, “If you’re active both before and after diagnosis, there are a lot of changes that occur in your blood,” such as in levels of insulin and other hormones. “There are a lot of systemic changes that occur that probably decrease your chance of recurrence and ultimately dying.” People in the study who exercised regularly were less likely to die in general and of cardiovascular disease – such as heart attacks and lung disease – in particular. For those patients, exercise likely has the same benefit as for cancer-free people, Campbell said. “Patients that have colon cancer, about two-thirds of them survive after five years and what they end up dying of is what all older people end up dying of, and that’s usually cardiovascular disease.” He said people with colon cancer should discuss with their doctors when they can get back to physical activity.