Subjects in both groups (AE and control) completed the weekly safety compliance log, which was mailed to the study investigator each week in order to keep regular up- dates on the subjects’ compliance to the study safety guide- lines, document any injury that a subject may have incurred during ordinary living or AE activity, and give the controls a sense of active participation in the study. Patients in the intervention group mailed a weekly log of their aerobic ex- ercise program, including length of exercise time, intensity of exercise (heart rate), and mode of exercise (walking or cycling). Because the exercise intervention was home based and unsupervised, both groups had equal personal contact with the study investigator.