Brief Vigorous Stair Climbing Effectively Improves Cardiorespiratory Fitness in Patients With Coronary Artery Disease: A Randomized Trial
Emily C. Dunford, Sydney E. Valentino, Jonathan Dubberley, Sara Y. Oikawa, Chris McGlory, Eva Lonn, Mary E. Jung, Martin J. Gibala, Stuart M. Phillips, Maureen J. MacDonald
Abstract
Background: Cardiac rehabilitation exercise reduces the risk of secondary cardiovascular disease. Interval training is a time-efficient alternative to traditional cardiac rehabilitation exercise and stair climbing is an accessible means. We aimed to assess the effectiveness of a high-intensity interval stair climbing intervention on improving cardiorespiratory fitness ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mover accent="true"><mml:mtext>V</mml:mtext><mml:mo>˙</mml:mo></mml:mover><mml:msub><mml:mtext>O</mml:mtext><mml:mrow><mml:mn>2</mml:mn><mml:mtext>peak</mml:mtext></mml:mrow></mml:msub></mml:math> ) compared to standard cardiac rehabilitation care. Methods: Twenty participants with coronary artery disease (61 ± 7 years, 18 males, two females) were randomly assigned to either traditional moderate-intensity exercise (TRAD) or high-intensity interval stair climbing (STAIR). <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"><mml:mover accent="true"><mml:mtext>V</mml:mtext><mml:mo>˙</mml:mo></mml:mover><mml:msub><mml:mtext>O</mml:mtext><mml:mrow><mml:mn>2</mml:mn><mml:mtext>peak</mml:mtext></mml:mrow></mml:msub></mml:math> was assessed at baseline, following 4 weeks of six supervised exercise sessions and after 8 weeks of ~24 unsupervised exercise sessions. TRAD involved a minimum of 30 min at 60–80%HR peak , and STAIR consisted of three bouts of six flights of 12 stairs at a self-selected vigorous intensity (~90 s/bout) separated by recovery periods of walking (~90 s). This study was registered as a clinical trial at clinicaltrials.gov (NCT03235674). Results: Two participants could not complete the trial due to the time commitment of the testing visits, leaving n = 9 in each group who completed the interventions without any adverse events. <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M3"><mml:mover accent="true"><mml:mtext>V</mml:mtext><mml:mo>˙</mml:mo></mml:mover><mml:msub><mml:mtext>O</mml:mtext><mml:mrow><mml:mn>2</mml:mn><mml:mtext>peak</mml:mtext></mml:mrow></mml:msub></mml:math> increased after supervised and unsupervised training in comparison to baseline for both TRAD [baseline: 22.9 ± 2.5, 4 weeks (supervised): 25.3 ± 4.4, and 12 weeks (unsupervised): 26.5 ± 4.8 mL/kg/min] and STAIR [baseline: 21.4 ± 4.5, 4 weeks (supervised): 23.4 ± 5.6, and 12 weeks (unsupervised): 25 ± 6.2 mL/kg/min; p (time) = 0.03]. During the first 4 weeks of training (supervised) the STAIR vs. TRAD group had a higher %HR peak (101 ± 1 vs. 89 ± 1%; p ≤ 0.001), across a shorter total exercise time (7.1 ± 0.1 vs. 36.7 ± 1.1 min; p = 0.009). During the subsequent 8 weeks of unsupervised training, %HR peak was not different (87 ± 8 vs. 96 ± 8%; p = 0.055, mean ± SD) between groups, however, the STAIR group continued to exercise for less time per session (10.0 ± 3.2 vs. 24.2 ± 17.0 min; p = 0.036). Conclusions: Both brief, vigorous stair climbing, and traditional moderate-intensity exercise are effective in increasing <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M4"><mml:mover accent="true"><mml:mtext>V</mml:mtext><mml:mo>˙</mml:mo></mml:mover><mml:msub><mml:mtext>O</mml:mtext><mml:mrow><mml:mn>2</mml:mn><mml:mtext>peak</mml:mtext></mml:mrow></mml:msub></mml:math> , in cardiac rehabilitation exercise programmes.