Perceived Effort Step-up Procedure for Self-Regulating Stationary Cycle Exercise Intensity by Patients with Cardiovascular Disease

Abstract

This study examined the strategy utilized by patients with cardiovascular disease to regulate exercise intensity using the Rating of Perceived Exertion (RPE) and tested if a step-up procedure would reduce overshoot of target heart rate (HR). Also the study investigated if Prescription Congruence and Intensity Discrimination, components of the Intensity Self-regulation Model, could be validated for these patients. An estimation and production paradigm was used. HR was measured at 2-min. intervals during 6-min. stationary cycle ergometer exercise trials. Data for four experimental trials were compared: (1) a work intensity set by experimenter to achieve a target RPE of 11 (Estimation 11), (2) an intensity set by experimenter to achieve a target RPE of 13 (Estimation 13), (3) an intensity varied by participant every 2 min. to produce a target RPE of 13 (Production 13), and (4) a Step-up Procedure with the intensity varied by participant, first producing a target RPE of 11 during the first 2 min., followed by producing a target RPE of 13 from min. 2 to 6 of exercise (Production 11 + 13). A very small effect size was found for HR between Production 13 and Estimation 13, and a moderate effect size was noted for the increased HR when patients produced a target RPE of 13 as compared to 11. The participants could be divided into 2 groups: 10 patients comprised a Higher group whose HR at 2 min. during Production 13 was greater than HR at 2 min. during Estimation 13, and 6 patients in a Lower group with HR at 2 min. during Production 13 less than or equal to HR during Estimation 13. A large effect size was found at 6 min. for the reductions of the Higher group's HR overshoot and for the Lower group's HR undershoot during Production 13. All participants in the Higher group (n=10) had a clinically significant HR overshoot of 5 beats x min.(-1) at 2 min. during Production 13. Using a Step-up Procedure (Production 11 + 13), a large effect size was found for the reduced number of patients (n=3) with an overshoot of 5 beats x min.(-1) at 2 min. This supports the ability of participants in cardiac rehabilitation programs to meet the Prescription Congruence and Intensity Discrimination components of the Intensity Self-regulation Model in the RPE 11-13 zone. Evidence was found for overshoot/undershoot of target HR at 2 min., supporting a proposed third component, Production Strategy, of the Intensity Self-regulation Model. The 2-min. Step-up Procedure reduced some patients' tendency to "overshoot" target intensity.