Chemotherapy-induced peripheral neuropathy (CIPN) is a severe dose-limiting toxicity that affects over 65% of patients receiving platinum-based chemotherapy for gastrointestinal cancers. Not only does CIPN increase mortality by limiting the dose of chemotherapy, CIPN affects walking, writing, eating, and dressing via numbness, tingling, pain, cold sensitivity, and cramping in the hands and feet. There are no FDA-approved treatments for CIPN because we need a greater understanding of the pathophysiology of CIPN and mechanisms of action of promising treatments for CIPN. In addition, most research on CIPN in humans has focused on taxane-based chemotherapy in patients with breast cancer. Here, we are focusing on platinum-based chemotherapy in patients with gastrointestinal cancers because taxane- and platinum-induced CIPN are both very common but exhibit distinct signs, symptoms, and mechanisms of toxicities, and may respond differently to a given treatment. This project is motivated by an innovative perspective that CIPN symptoms are not due simply to peripheral nerve damage, but rather that CIPN symptoms are worsened by damage to the interoceptive brain system—which processes sensations from the body—as well as systemic inflammation. This is a Phase II randomized clinical trial to assess the effects of 12 weeks of exercise during platinum chemotherapy on CIPN, interoception, and inflammation in 60 patients with gastrointestinal cancer. The specific aims of this project are to assess the effects of exercise vs. nutrition education (control) on: (1) patient reported CIPN, (2) clinical assessments of CIPN (tactile sensitivity and cold-induced pain), (3) interoception (functional connectivity in the interoceptive brain system and self-report), and (4) inflammation (serum inflammatory cytokines). This is the first study to examine the effects of exercise during platinum chemotherapy on CIPN and to examine roles of interoception and inflammation in the treatment of platinum-induced CIPN. Results from this study will inform an R01 application to more definitively assess this theory of CIPN and exercise. If this work is successful, we will have identified an effective intervention (exercise) for alleviating CIPN and we will have a better understanding of how exercise alleviates CIPN (i.e., interoception and inflammation). We believe this knowledge can be applied to improve prediction, tracking, sub-typing, and treatment of CIPN using exercise or other interventions that affect these pathways. This will ultimately help alleviate the burden of chemotherapy on treating patients with cancer.