The maximal heart rate (HRmax) in the exercise prescription was based on age [Goldberg, Elliot, and Kuehl1988] and reduced by 20% in participants who used beta-blockers [Wonisch et al. 2003]. The duration of exercise sessions (3x/week) was advanced from 15 to 45 minutes over the first 6 weeks. The goal for continuous training was to remain within 70-80% of HRmax throughout the session. Interval trainees alternated every 3 minutes between slower (60-70% of HRmax) and faster (80-90% of HRmax) walking[Wisloff et al. 2007]. We emphasized that these parameters were for guidance only and that the participants should give their best effort without feeling uncomfortable or unsafe.