Caffeine does not change incremental test performance and autonomic recovery response in COPD patients

Aim The aim of this study was to verify the influence of caffeine (CAF) on time to exhaustion in a maximal incremental exercise test and cardiac autonomic indexes recovery in chronic obstructive pulmonary disease (COPD) patients.Methods In a randomized, double-blinded, placebo-controlled and crossover experimental design, eleven patients diagnosed with COPD performed an incremental test after ingesting CAF (5 mg kg(-1)) or placebo (PLA) (cellulose). CAF or PLA was administered 60 min before the test. Peripheral oxygen saturation was analyzed throughout the tests. Heart rate recovery (HRR) and variability (HRV) were analyzed after exhaustion in both tests. Additionally, six patients completed a spirometry after ingesting a capsule of caffeine.Results The time to exhaustion in the incremental test with CAF (355.8 +/- 171.1 s) was 2.1% longer than in the PLA test (348.5 +/- 209.1 s), but there was no statistical difference (p = 0.70). Similarly, no statistical differences were observed in HRR and HRV between PLA and CAF (p > 0.05 for all analyses). The peripheral oxygen saturation values were lower at exhaustion but without a statistical difference (CAF = 92.3 +/- 4.4% vs. PLA = 91.5 +/- 2.7%; p > 0.05). After spirometry, the effect of CAF on FEV1 (Before CAF = 1.43 +/- 0.75 L vs. After CAF = 1.47 +/- 0.70 L; p = 0.17) was not demonstrated.Conclusion Caffeine does not change incremental test performance and autonomic recovery response in patients with COPD. These results suggest caffeine would not have an ergogenic effect in patients with COPD.