Repeatability and Meaningful Change of CPET Parameters in Normal Subjects.

Introduction/Purpose: Cardiopulmonary exercise testing (CPET) plays an important role in clinical medicine and research. Repeatability of CPET parameters has not been well characterized, but is important to assess variability and determine if there have been meaningful changes in a given CPET parameter. Methods: We recruited 45 healthy subjects and performed two symptom-limited CPETs within 30 days using a cycle ergometer. Differences in relevant CPET parameters between CPET-1 and CPET-2 were assessed using a paired t-test. Coefficient of variation (CoV) and Bland-Altman plots are reported. Factors that may be associated with variability were analyzed (sex, age, time of day, fitness level). The coefficient of repeatability was calculated for peak V[spacing dot above]O2 and V[spacing dot above]O2 at lactate threshold (LT) to establish a 95% threshold for meaningful change. Results: There were no significant differences between tests in the parameters reported. Specifically, we found overall low CoV in peak V[spacing dot above]O2 (4.9%), V[spacing dot above]O2@LT (10.4%), peak O2 pulse (4.6%), peak V[spacing dot above]E (7.4%), V[spacing dot above]E/V[spacing dot above]CO2@LT (4.0%) andV[spacing dot above]E/V[spacing dot above]O2@LT (4.8%). The CoV for RER@LT was significantly affected by diurnal factors; age, sex and fitness level did not impact variability. The 95% threshold for meaningful change in peak V[spacing dot above]O2 was 0.540 L/min and for V[spacing dot above]O2@LT was 0.520 L/min. Conclusions: Repeatability of CPET parameters is generally higher then previously reported. There were no significant differences in variability related to sex, age, fitness level; diurnal factors had a limited impact. The threshold for meaningful change in peak V[spacing dot above]O2 and for V[spacing dot above]O2@LT should be considered when gauging a response to therapies or training. (C) 2017 American College of Sports Medicine

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