The goal of this study is to determine if 12 weeks of cycling exercise training at home will improve three parameters: 1) blood pressure, 2) cognition, and 3) walking ability among persons with multiple sclerosis who have high blood pressure, when compared to a group that engages in a 12-week home-based stretching program. The main questions this study aims to answer are: 1. Can home-based cycling exercise training improve blood pressure by increasing blood vessel dilation in people with multiple sclerosis? 2. Can cycling exercise training improve cognition and walking mobility in people with multiple sclerosis by improving blood pressure? The investigators will compare home-based cycling training to stretching to see if cycling training improves cognition, walking mobility, blood pressure, and fitness in people with multiple sclerosis. Participation in this study will take 13-14 weeks, with participants being randomized (like flipping a coin, a 50-50 chance of being in either group) to the home-based cycling training or the stretching group. All participants will be asked to * Visit the laboratory two times, one before the beginning of the intervention (home-base training and stretching group) and one at the end of the intervention. * During visits, participants will complete tests related to cognition, walking mobility, blood pressure and fitness.