A standardized approach to evaluate effectiveness of aerobic exercise training interventions in cardiovascular disease at the individual level.

Background: Reliable change indices can determine pre-post intervention changes at an individual level that are greater than chance or practice effect. We applied previously developed minimal meaningful change (MMC) scores for oxygen uptake (V̇O) values associated with estimated lactate threshold (θ), respiratory compensation point (RCP), and peak oxygen uptake (V̇O) to evaluate the effectiveness of exercise training in cardiovascular disease patients.

Methods: 303 patients (65 ± 11 yrs.

Quantifying Improvement in V˙ o2peak and Exercise Thresholds in Cardiovascular Disease Using Reliable Change Indices.

Purpose: Improving aerobic fitness through exercise training is recommended for the treatment of cardiovascular disease (CVD). However, strong justifications for the criteria of assessing improvement in key parameters of aerobic function including estimated lactate threshold (θ LT ), respiratory compensation point (RCP), and peak oxygen uptake (V˙ o2peak ) at the individual level are not established. We applied reliable change index (RCI) statistics to determine minimal meaningful change (MMC RCI ) cutoffs of θ LT , RCP, and V˙ o2peak for individual patients with CVD.

Do Clinical Exercise Tests Permit Exercise Threshold Identification in Patients Referred to Cardiac Rehabilitation?

Background: To evaluate the feasibility of "threshold-based" aerobic exercise prescription in cardiovascular disease, we aimed to quantify the proportion of patients whose clinical cardiopulmonary exercise test (CPET) permit identification of estimated lactate threshold (θ) and respiratory compensation point (RCP) and to characterize the variability at which these thresholds occur.

Methods: Breath-by-breath CPET data of 1102 patients (65 ± 12 years) referred to cardiac rehabilitation were analyzed to identify peak O uptake (V˙O; mL·min and mL·kg·min) and θ and RCP (reported as V˙O, %V˙O, and %peak heart rate [%HR]). Patients were grouped by the presence or absence of thresholds: group 0: neither θ nor RCP; group 1: θ only; and group 2: both θ and RCP.

Strategies to improve respiratory chemoreflex characterization by Duffin's rebreathing.

New Findings: What is the central question of this study? We assessed the test-retest variability of respiratory chemoreflex characterization by Duffin's modified rebreathing method and explored whether signal averaging of repeated trials improves confidence in parameter estimation. What is the main finding and its importance? Modified rebreathing is a reproducible method to characterize responses of central and peripheral respiratory chemoreflexes. Signal averaging of multiple repeated tests minimizes within- and between-test variability, improves the confidence of chemoreflex characterization and reduces the minimal change in parameters required to establish an effect.