Effects of different exercise training programs on post-exercise [Formula: see text]O₂ recovery responses in patients with coronary heart disease

PURPOSE: Oxygen deficit (O2 deficit) and post-exercise oxygen uptake ([Formula: see text]O2) recovery responses are clinical prognostic markers in cardiac patients but have not been studied after exercise training in patients with coronary heart disease (CHD). We aimed to compare the effects of different modalities of exercise training on O2 deficit and post-exercise [Formula: see text]O2 responses in CHD patients. METHODS: From a pooled analysis of three randomised control trial, patients with CHD were trained with moderate-intensity continuous exercise training (MICET), low volume high-intensity interval training (LV-HIIT), or combined MICET/HIIT for 12 weeks. Cardiopulmonary exercise test (CPET) parameters were assessed, and key exercise variables were calculated during and after exercise. O2 deficit, CPET post-exercise kinetics time constant for oxygen uptake ([Formula: see text]O2), carbon dioxide ([Formula: see text]CO2), minute ventilation ([Formula: see text]E) and heart rate (τHR), O2 debt and [Formula: see text]O2 recovery delay (RD) were calculated before and after training. RESULTS: A significant training effect for [Formula: see text]O2 (p < 0.05) was shown for all groups. Shorter [Formula: see text]O2 values with small effect size (ES from 0.21 to 0.4) were noted for the combined MICET/HIIT and MICET groups. A significant training effect (p < 0.01) was noted for O2 debt that was increased after training (ES: 0.1 to 0.47). No significant statistical effect was shown for [Formula: see text]O2 RD and [Formula: see text]CO2, [Formula: see text]E, τHR and O2 deficit in all groups. CONCLUSIONS: In patients with CHD, exercise training improved post-exercise [Formula: see text]O2 kinetic and the O2 debt, with a higher impact of exercise dose (combined MICET/HIIT). Exercise training did not improve the [Formula: see text]O2 RD or the recovery time constant value of other cardiorespiratory parameters in CHD patients. TRIAL REGISTRATION: NCT03414996, NCT02048696, NCT03443193.