Heart Rate Variability-Guided Exercise Training Compared With Standard Exercise Training in Patients With Coronary Artery Disease: A RANDOMIZED CLINICAL TRIAL.

PURPOSE This study aimed to compare heart rate variability-guided (HRV-G) exercise training versus standard exercise training (SET) on peak oxygen uptake (V̇O₂peak) in patients experiencing an acute coronary syndrome event.

METHODS This randomized controlled trial included 48 patients randomized to HRV-G or SET. Both groups consisted of 3 aerobic exercise sessions per week for 3 months. For the HRV-G group, daily exercise was based on a 5-minute morning heart rate recording and the root mean square of successive differences between normal heartbeats (RMSSD). If RMSSD was within ±0.5 SD from baseline, a high-intensity interval training session was performed; if beyond ±0.5 SD, an active recovery session was prescribed. The SET group did 2 sessions of moderate-intensity continuous exercise and 1 session of high-intensity interval training per week, irrespective of HRV status.

RESULTS The V̇O₂peak increased significantly in both groups (+1.9 mL·kg-1·min-1, P = .002 for SET and +2.1 mL·kg-1·min-1, P < .001 for HRV-G) with no significant group-by-time interaction (P = .794). Fifty percent of patients were considered responders (ΔV̇O₂peak change post-pre >5%) in the SET group versus 75% in the HRV-G group (P = .111). There was a significant time-by-group interaction for V̇O2 at the first ventilatory threshold, adjusted for lean body mass, showing greater improvement in the HRV-G group compared with the SET group (P = .043). The training load was significantly lower in HRV-G.

CONCLUSIONS In patients with coronary artery disease, HRV-G exercise training led to similar V̇O₂peak improvements and prevalence of responders but a larger improvement in V̇O2 at the first ventilatory threshold adjusted for lean body mass compared with SET, despite a lower training load.