Autonomic Effects of Spinal Cord Stimulation in Spinal Cord Injury

The goal of this interventional crossover study is to determine the effects of transcutaneous spinal cord stimulation (TSCS) on the ability to perform moderate exercise and regulate core body temperature in the chronic spinal cord injury community. The main questions it aims to answer are: * What are the effects of active TSCS targeted for BP control on exercise endurance time and HR recovery during submaximal arm cycle ergometry (ACE) as compared to sham TSCS in participants with chronic, cervical SCI? * What are the effects of active TSCS on Tcore responses to cool ambient exposure and on subjective reporting of thermal comfort and thermal sensitivity as compared to sham TSCS. Participants will receive sham and active stimulation while using an arm bicycle or while in a cold room. Participants are free to participate in either the exercise phase, the cold room phase, or both phases of this study. Please note that there no expected long term benefits of this study.