Cardiorespiratory Fitness Prediction in Vestibular Hypofunction: Does One Size Fit All?

Cardiorespiratory fitness is a strong predictor of health and mortality. However, its gold-standard assessment, peak oxygen uptake via cardiopulmonary exercise testing, is not always feasible in clinical practice. This study aimed to (1) develop exercise-based cardiorespiratory fitness prediction models for people with vestibular hypofunction and (2) evaluate the applicability of existing models to this population. Fifty-four adults with unilateral or bilateral vestibular hypofunction (56% women) completed maximal cardiopulmonary exercise testing for peak oxygen uptake determination. Cardiorespiratory fitness prediction models were developed using maximal vestibular hypofunction and submaximal vestibular hypofunction (vestibular hypofunction-specific submaximal prediction model with gas-based analysis and vestibular hypofunction-specific submaximal prediction model without gas-based analysis) test characteristics. A 100-fold repeated cross-validation assessed model accuracy, maximal vestibular hypofunction (r=0.90 and standard error of the estimate=3.0), vestibular hypofunction-specific submaximal prediction model with gas-based analysis (r=0.86 and standard error of the estimate=3.6), and vestibular hypofunction-specific submaximal prediction model without gas-based analysis (r=0.79 and standard error of the estimate=4.3) showed high predictive accuracy, with minimal bias (< 1%). Existing equations misestimated cardiorespiratory fitness (effect size=0.56-0.68, large). Predictions within one or more metabolic equivalent of task were higher for vestibular hypofunction models, reaching up to 8-9 out of 10 individual cases. The newly developed vestibular hypofunction-specific models offer more accurate, clinically applicable tools for cardiorespiratory fitness estimation across various clinical scenarios, including settings where maximal testing is not feasible. An automated calculator was developed to support clinical implementation in vestibular hypofunction management.