Cardiopulmonary exercise tests in people with chronic stroke: Interpretation and clinical application

ObjectiveTo understand in people with stroke: (1) reasons for cardiopulmonary treadmill exercise test termination, (2) how frequently secondary criteria indicating a maximal test are met, and (3) how test termination is related to volume of oxygen consumption and participant characteristics.DesignA secondary analysis from the Promoting Recovery Optimization of Walking Activity in Stroke (NCT02835313) clinical trial.SettingFour outpatient rehabilitation clinics.ParticipantsPeople with chronic stroke able to walk without assistance of another person.InterventionParticipants (n = 250) randomized in a larger clinical trial completed symptom limited graded exercise treadmill tests pre- (n = 247) and post-intervention (n = 185). Treadmill exercise tests were conducted at constant speed with incremental incline increases.Main MeasuresThe primary measure was reason for cardiopulmonary exercise test termination. Secondary measures included: oxygen consumption, ventilatory threshold, peak heart rate, respiratory exchange ratio, six-minute walk test, and fastest walking speed.ResultsThere were six categories of test termination, electrocardiogram (11%), blood pressure/heart rate (13%), biomechanical (25%), self-selected (41%), equipment malfunction (8%), and other (2%). Only 1.9% of tests achieved the threshold to confirm a maximal aerobic effort. There were no differences in peak volume of oxygen consumption or participant characteristics between test termination categories.ConclusionsAnalyses indicate few with chronic stroke exhibit a maximal aerobic effort on a cardiopulmonary exercise test. If the cardiorespiratory system is not thoroughly taxed during treadmill exercise tests in people with chronic stroke, interpreting results as their cardiorespiratory fitness should be done cautiously.