A Study on the Effects of Exercise on Side Effects From Treatment for Gastrointestinal Cancers

The purpose of this study is to find the level of aerobic exercise (AT) that is practical, is safe, and has positive effects on the body that may reduce the side effects of therapy. The study will also look at the way the body responds to exercise and whether there are differences in treatment. This will include looking at the highest treatment dose participants receive, how many people stop, delay, or reduce the treatment, and whether additional medication is needed to treat side effects of therapy.