Cardiorespiratory Fitness in Individuals Post-stroke: Reference Values and Determinants

Objective: To provide reference values of cardiorespiratory fitness for individuals post-stroke in clinical rehabilitation and to gain insight in characteristics related to cardiorespiratory fitness post stroke. Design: A retrospective cohort study. Reference equations of cardiopulmonary fitness corrected for age and sex for the fifth, 25th, 50th, 75th, and 95th percentile were constructed with quantile regression analysis. The relation between patient characteristics and cardiorespiratory fitness was determined by linear regression analyses adjusted for sex and age. Multivariate regression models of cardiorespiratory fitness were constructed. Setting: Clinical rehabilitation center. Participants: Individuals post-stroke who performed a cardiopulmonary exercise test as part of clinical rehabilitation between July 2015 and May 2021 (N=405). Main Outcome Measures: Cardiorespiratory fitness in terms of peak oxygen uptake (V˙O2peak) and oxygen uptake at ventilatory threshold (V˙O2-VT). Results: References equations for cardiorespiratory fitness stratified by sex and age were provided based on 405 individuals post-stroke. Median V˙O2peak was 17.8[range 8.4-39.6] mL/kg/min and median V˙O2-VT was 9.7[range 5.9-26.6] mL/kg/min. Cardiorespiratory fitness was lower in individuals who were older, women, using beta-blocker medication, and in individuals with a higher body mass index and lower motor ability. Conclusions: Population specific reference values of cardiorespiratory fitness for individuals post-stroke corrected for age and sex were presented. These can give individuals post-stroke and health care providers insight in their cardiorespiratory fitness compared with their peers. Furthermore, they can be used to determine the potential necessity for cardiorespiratory fitness training as part of the rehabilitation program for an individual post-stroke to enhance their fitness, functioning and health. Especially, individuals post-stroke with more mobility limitations and beta-blocker use are at a higher risk of low cardiorespiratory fitness.