Cardiopulmonary response during incremental shuttle walking test in a hallway versus on treadmill in Phase IV cardiac rehabilitation: a cross-sectional study

There is widespread use of incremental shuttle walking test (ISWT) to measure functional capacity in cardiac rehabilitation patients. Due to occasional physical space limitations, an incremental shuttle walking test on a treadmill (ISWT-T) was suggested as an alternative. Knowledge about the cardiopulmonary response between the two tests and the factors associated with the distance achieved in Phase IV cardiac rehabilitation is limited. Thus, the study aims to compare the cardiopulmonary response between ISWT and ISWT-T and investigate the factors associated with distance achieved in both tests. Thirteen participants (66.3 ± 7.3 years, 84.6% males) attending phase IV cardiac rehabilitation participated in repeated measures counterbalanced trials. Each participant performed one ISWT and one ISWT-T separated by seven days. Main outcome measures included peak heart rate (HR), systolic and diastolic blood pressure post-test, distance achieved, respiratory frequency, tidal volume (VT), minute ventilation, respiratory exchange ratio, peak oxygen uptake (VO_2PEAK), and secondary outcome measures included height, weight, waist circumference (WC) leg length (LL). There were no significant differences in the cardiopulmonary responses between ISWT and ISWT-T except for VO_2PEAK (25.4 ± 5.8 vs 23.7 ± 5.1, p = 0.05, respectively). Age and height were significantly correlated with distance achieved during ISWT, and ISWT-T [age (r = − 0.72, vs. r = − 0.73, p ≤ 0.05, respectively)], [height (r = 0.68, vs. r = 0.68, p ≤ 0.05, respectively)]. LL was only correlated with distance achieved on ISWT-T (r = 0.59, p ≤ 0.05). These findings suggest a similar cardiopulmonary response between the two tests, but doing ISWT in the hallway evoked a higher metabolic demand than doing it on a treadmill. Additionally, distance achieved on both tests was related to height and inversely to age.