Effects of Heart Rate Variability-guided Training vs Standard Aerobic Prescription on Cardiovagal Modulation and Cardiorespiratory Fitness in Coronary Artery Disease

Over the first 4 weeks, participants will perform 4 bouts of 2 min of high-intensity exercise at 80-90% heart rate reserve (HRR), during the next 4 weeks, participants will perform 6 bouts of 2 min of high-intensity exercise at 80-90%HRR, while in the last 4 weeks participants will perform 6 bouts of 2 min of high-intensity exercise at 90%HRR). Exercise bouts will be interspersed by 2 min of active recovery at 50-60% HRR.

Over the first 4 weeks participants in MICT will perform continuous exercise at 50-60% HRR (2x10'), during the next 4 weeks participants will perform continuous exercise at 50-60% HRR (2x12'), while in the last 4 weeks participants will perform continuous exercise at 60-70% HRR (2x15').

"Following a 10-day initial characterization period, where the HRV is measured with plethysmography continually during the night, with Whoop (https://www.whoop.com) device, the individual HRV profile is defined, still, participants will use the Whoop during all intervention to allow the updating of HRV profile. Then, considering the daily individual autonomic regulation, following a decision-making schema modified from Kiviniemi et al., (2007) \[21\], exercise intensity will be defined for the training session, i.e., if LnRMSSD7day-roll-avg remained inside the smallest worthwhile change (SWC) (SWC = 0.5 × standard deviation), high intensity or moderate-intensity training sessions is prescribed, if LnRMSSD7day-roll-avg fell outside SWC, low intensity or rest is prescribed, leading to different workloads from the predefined training programs."