2.3. Exercise Protocol
Subjects in the combination group and exercise group performed moderate-intensity aerobic training 5× per week for 3 months. Every exercise session was supervised by the study coordinator. Treadmills, stationary bikes, or elliptical machines were used for the aerobic training. Each training session was performed at the research center. The maximum predicted heart rate (HRmax) was calculated as [(210/min-age)] for women and [(220/min-age)] for men. An activity monitor was used to evaluate Hrmax. Exercise intensity increased over the first 4 weeks of the trial (i.e., from 65 to 80% of Hrmax). The exercise lasted for 60 min per session. Approximately 3 months into the study, the COVID pandemic hit, and subjects transitioned to at-home training using their own exercise equipment. If they did not have any equipment at home, they were instructed to watch aerobic exercise videos on the internet. The training sessions at home were supervised by the study coordinator using video conference platforms. Subjects in the ADF group and control group did not perform the exercise intervention. These subjects were asked not to change their daily activity routines, so as to not confound the study findings. 