Novel Measures to Evaluate the Cardiorespiratory Response to Exercise Training Without a Follow-up Exercise Test

Quantifying the cardiorespiratory response to exercise training (CR-ExT) without a follow-up maximal exercise test is a challenge faced by cardiac rehabilitation programs; a valid measure derived from typical exercise session data would be useful. PURPOSE: Describe the relationship between changes in novel measures of CR-ExT derived from submaximal exercise data to changes in (a) submaximal measured O2 pulse and (b) peak VO2. METHODS: This secondary analysis of the HERITAGE Family Study used baseline and follow-up (20 wk exercise training) maximal and submaximal (60% VO2 peak) leg ergometry data, both with respiratory gas analysis (healthy; aged ≥30 yr; n= 306; 43% male). Using work rate from the submaximal test, estimated submaximal VO2 (mL/min) and METs were calculated. Estimated VO2, estimated METs, and submaximal work rate were divided by heart rate and termed estO2pulse, estMET-pulse, and Watt-pulse, respectively. RESULTS: Baseline peak VO2 was 27.0±6.7 mL/kg/min (mean±SD) and increased 19±10% at follow-up (p<0.001). Submaximal O2 pulse, estO2pulse, MET-pulse, and Watt-pulse increased 19±11%, 24±14%, 25±15%, and 44±35%, respectively (p<0.001 for each). At follow-up, % change of each proposed CR-ExT parameter showed a moderate correlation (0.68-0.78) with % change in submaximal measured O2 pulse, but a lower correlation (0.33-0.45) with % change in peak VO2 (Table). CONCLUSIONS: Changes in proposed CR-ExT parameters were related to a traditional measure of CR-ExT (i.e., change in submaximal O2 pulse) with SEE of 7-8%. These parameters can be determined using typical exercise session data and could serve as program outcomes; however, this variability may limit ability to accurately evaluate individual patient response.Table