Relationships of Affect and Neuroinflammation With Clinical Pain in Veterans With Fibromyalgia

6-week structured exercise intervention. The intervention will include twice weekly, center-based, aerobic exercise consisting of continuous treadmill walking. Each center-based session will include 45 minutes of aerobic exercise in addition to balance and flexibility exercises to promote cool-down. During each exercise session, they will also be asked to wear a heart rate monitor to measure mean pulse during their exercise sessions.