Cardiorespiratory Effects of Tai Chi Versus Walking: Exploratory Data from the LEAP Trial

Abstract

Tai Chi (TC), a mind-body exercise, may be a potential exercise maintenance strategy for patients with chronic obstructive pulmonary disease (COPD) after pulmonary rehabilitation. We sought to characterize the acute cardiorespiratory response during TC versus walking in patients with COPD after a 24-week intervention. Cardiorespiratory data were available on 26 adults with COPD (46% female, 54% GOLD stage III–IV) randomized to TC (n = 19) or group walking (n = 7). At 24 weeks, we examined between-groups standard cardiorespiratory measures (heart rate (HR), oxygen consumption (VO2), expired carbon dioxide (VCO2), respiratory rate (RR), and ventilation (VE)) during a multiphase in-class characterization protocol. Continuous HR data during resting and exercise phases were analyzed for time- and frequency-domain HR variability (HRV) indices. At 24 weeks, during exercise phases, those in TC exhibited a mean HR of 80 ± 15 b · min−1, RR of 16.5 ± 4 breaths·min−1, and VO2 of 434.8 ± 146.5 mL·min−1; and in walking 95.7 ± 9.2 b·min −1, 26.2 ± 8 breaths·min−1, and 901.3 ± 261.2 mL·min−1, respectively (P < 0.05). Overall, TC was less strenuous with lower HR, VO2, VCO2, RR, and VE (P < 0.05). At rest, TC demonstrated more favorable respiratory efficiency (VE/VCO2; 35.53 ± 5.65 versus 41.07 ± 5.21, P < 0.05). During the postexercise recovery phase, time-domain HRV indices decreased after walking (e.g., pNN20: 35.7 ± 24.1 baseline, 10.3 ± 9.5 postwalk; pNN50: 20.9 ± 18.5 baseline, 3.9 ± 3.7 postwalk), while they remained relatively unchanged after TC. Frequency-domain HRV measures suggested greater total power (TP) across all phases of TC versus walking, particularly during meditation (P < 0.05 for LnTP). Preliminary data support that TC may be associated with improved pulmonary efficiency and reduced rapid shallow breathing compared with walking and be a viable exercise maintenance option after pulmonary rehabilitation.