Background: Interval training is well tolerated and recommended to enhance exercise capacity and alleviate respiratory symptoms during pulmonary rehabilitation in all stages of chronic obstructive pulmonary disease (COPD). Sprint interval training (SIT) is a new modality of interval training which has been found to improve both aerobic and anaerobic performance in healthy and sedentary populations. Cardiovascular disorders alongside with exertional dyspnea are major limitations of exercise tolerance in COPD. Therefore, SIT may favor cardiovascular adaptation and reduce respiratory symptoms irritations during high-intensity training with COPD patients.
Aim: To investigate the effect of short-term SIT on cardiovascular function and aerobic performance in patients with COPD and healthy elderly individuals.
Methods: Two groups of COPD patients (n = 10, age = 70.7 ± 7.7 years) and matched elderly subjects (n = 9, age = 65.4 ± 3.6 years) were recruited to perform SIT. Stroke volume (SV) and cardiac output (CO) were assessed using impedance cardiograph during rest, standard workload and maximal exercise test at baseline and after the training intervention. Exercise time to exhaustion was assessed at baseline and after SIT. The anaerobic performance was analyzed from changes in peak power during SIT from the second to the last training session. SIT program consisted of repeated 4 sprint bouts (20 sec) with all-out effort interspersed with 3-5 minutes recovery time for 3 weeks.
Results: Eight subjects in each group completed 3 weeks of SIT. In both the COPD and healthy group, no significant changes found in peak stroke volume (SVpeak; p = 0.66 vs p = 0.71, respectively) and peak cardiac output (COpeak; p = 0.68 vs p = 0.47, respectively) during incremental exercise test. The results showed significant decrease in resting systolic blood pressure (SBP) in both COPD (139.1 ± 15.0 mmHg vs 130.6 ± 9.7 mmHg, P = 0.04) and healthy (128.6 ± 9.4 mmHg vs 122.8 ± 11.0 mmHg, p = 0.02) groups. The analysis showed a dramatically improvement in aerobic performance during cycle time to exhaustion (TTE) in both groups (COPD, 460.3 ± 361.5 sec vs 686.8 ± 511.3 sec, p = 0.04, Healthy, 489.3 ± 343.6 sec vs 831.0 ± 492.8 sec, p = 0.009). Peak power output (PPO) increased significantly from the second to the last SIT session in COPD and healthy groups (14.0% p < 0.01 vs 18.8% P = 0.01, respectively).
Conclusion: Short-term SIT is insufficient to improve central adaptations for SV and CO during exercise despite reduced peripheral vascular resistance at rest and improved aerobic performance during cycle to exhaustion with COPD patients and healthy elderly individuals.
Keywords: Cardiovascular function, Stroke volume, COPD, Sprint interval training||