Is postexercise hypotension a method-dependent phenomenon in chronic stroke? A crossover randomized controlled trial

Abstract

Background: This study assessed the reproducibility of postexercise hypotension (PEH) detection after two bouts of mixed circuit training (MCT) using three approaches that accounts the pre-exercise values and/or a control session (CTL) to calculate PEH [i.e., ((Formula presented.)); (Formula presented.); (Formula presented.) in chronic stroke (i.e., ≥6 months poststroke). The proportion of PEH responders determined using different cut-off values for PEH was also compared (4 mmHg vs. minimal detectable difference). Methods: Seven participants (age: 56 ± 12 years; time post-stroke: 91 ± 55 months) performed two bouts of MCT and a CTL. The MCT involved 10 exercises with 3 sets of 15-repetition maximum, with each set interspersed with 45 s of walking. The systolic (SBP) and diastolic (DBP) blood pressures were assessed 10-min before and every 10-min along 40-min after CTL and MCT. Results: The two-way random intraclass correlation coefficient for single measurements (ICC2,1) ranges for SBP were: A1: 0.580−0.829, A2: 0.937−0.994, A3: 0.278−0.774; for DBP: A1: 0.497−0.916, A2: 0.133−0.969, A3: 0.175−0.930. The proportion of PEH responders detected using 4 mmHg or the minimal detectable difference as cut-off values was not different in 97% of analyses (p > 0.05), and higher when using 4 mmHg in 3% of analyses (p = 0.031). The standard error of measurement was ≥4 mmHg in 47% of analyses for SBP, and 40% for DBP. Conclusions: The most reliable approach for determining PEH in chronic stroke was to subtract the postexercise from the post-CTL values. The proportion of PEH responders was not affected by the cut-off values applied.