Responsiveness to Acute Changes in Exercise and Relaxation (RACER) Trial

It is hypothesized that the combination of aerobic exercise and relaxation training could have additive effects on fatigue and related cognitive outcomes. Therefore, this study is designed to test the effects of exercise plus relaxation relative to aerobic exercise alone and relaxation training alone, over the course of three sessions within a seven day period. Participants will complete baseline and post-testing before and after the week of training, as well as pre- and post-testing at each session. Participants will be randomized to one of three conditions: 1. Aerobic Exercise Only Condition (AERO) Participants randomized to the AERO condition will engage in three separate 20-minute sessions comprised of a 5-minute, resistance-free warm-up, and 15 minutes of moderate aerobic cycling on a stationary bike (50-70% age-predicted heart rate max). Each AERO session will end with a 20-minute quiet rest period. 2. Relaxation Only Condition (RELAX) Participants in the RELAX condition will complete three separate 20-minute sessions of relaxation training using a commercial neurofeedback device (headset \& smartphone app). Each RELAX session will end with a 20-minute quiet rest period. 3. Aerobic Exercise and Relaxation Training - Intervention Condition (COMBINED) Participants randomized to the COMBINED condition will complete three separate sessions comprised of 20 minutes of AERO exercise followed by 20 minutes of RELAX training. All participants, regardless of condition will complete brief questionnaires assessing in-the-moment fatigue and affect, before and after each randomly assigned activity session. A larger survey and battery of cognitive tests will be completed at the beginning of the first appointment and at the conclusion of the third appointment.