Exercise Program

After treadmill adaptation (1week), animal aerobic interval training was performed with a treadmill (DSPT-202, China) for 1h per time and five times per week for 8weeks. The training protocol consisted of a 5-min warm-up, a 6-min cool-down with 50–55% maximal oxygen uptake (VO_2max), and seven interval training periods (4min intervals at 80–90% VO_2max interspersed with 3min periods of 65–70% VO_2max). The VO_2max was measured through an incremental speed protocol (increased by 5m/min every 3min until the rats were exhausted) with a 0° slope treadmill and Columbus Oxymax Lab Animal Monitoring System (Columbus, United States; Qin et al., 2020a). Then the exercise intensity (80–90% VO_2max and 65–70% VO_2max) corresponding to different treadmill speeds were quantified, respectively.