InvestigatingRecovery From Maximal Exercise In Patients With Neuromuscular Disease

INTRODUCTION: Patients with neuromuscular disease (NMD) have low physical activity levels and increased risk of cardiovascular and pulmonary disease. Respiratory gas kinetics obtained during Cardiopulmonary Exercise Testing (CPET) may provide valuable insights into disease mechanisms and cardiorespiratory fitness in patients with NMD. Recovery from exercise is crucial for exercise performance and overall physical health, and impaired recovery is associated with various health conditions. This study applies respiratory gas analyses to investigate recovery from peak exercise in patients with NMD. METHODS: Patients with NMD being seen for clinical care and healthy volunteers were recruited for the study. CPET was performed to maximal exertion using a portable wearable metabolic system and a wheelchair-accessible total body trainer. The main recovery metrics were (i) time to reach 50% of peak oxygen consumption (T1/2 VO2) and (ii) the ratios of respiratory gasses between peak exercise and the highest values observed during recovery (overshoot). All participants gave informed consent and there were no adverse events during the trial. RESULTS: 34 patients with NMD and 15 controls were enrolled in the study. There was no significant difference in demographics or BMI between NMD and control groups (24.14 vs. 24.45). Peak exercise metrics were consistently lower in the NMD group compared to the control group (peak VO2: 20.2 ± 6.85 ml/kg/min vs. 35.9 ± 10.3 ml/kg/min). In terms of recovery variables, the NMD group had longer recovery times for T1/2 VO2: 108 ± 44.7 s vs 76 ± 36.4 s) and lower overshoot values for respiratory exchange ratio (28.8 ± 9.03% vs 14.5 ± 13.2%) and ventilation/VO2 (26.4 ± 28.4 vs 52.2 ± 23.5) compared to the control group. CONCLUSION: The current study observed impaired recovery metrics following peak exercise in patients with NMD compared to matched controls. Recovery metrics can provide important information on response to exercise interventions and provide guidance on exercise prescriptions.