Performance and Physiological Improvements in Treadmill Walking after 12 Sessions of Phase Two Cardiac Rehabilitation

Abstract

The benefit of cardiac rehabilitation (cardiac rehab) after a heart attack has been shown to decrease mortality and increase quality of life. PURPOSE: To determine the changes in treadmill walking time, speed and distance as well as pre- and post-exercising blood pressure (BP) and heart rate (HR) over the first 12 of 36 cardiac rehab sessions. METHODS: De-identified data from the charts of 16 post-myocardial infarction patients (13 men, 3 women; 58 ± 7 yrs, 83.8 ± 17.1 kg) who began the UNM Hospital Phase 2 cardiac rehab program between June and August of 2016 were evaluated. At intake, all patients participated in a modified Bruce protocol which was terminated when the patients reached a rating of perceived exertion (RPE) of 15 on the 6-20 Borg scale. Test results were used to prescribe patients’ respective initial walking speeds for the program. Patients walked at least twice weekly at their designated speed. Walking time and speed were adjusted regularly to keep an RPE of 13. Treadmill walking time, speed, distance, and heart rate (HR) were recorded and analyzed across the 1st, 6th, and 12th sessions through separate applications of the repeated measures ANOVA technique with post-hoc Bonferroni adjustment. The changes between pre- and post-walking bout blood pressure (BP) and HR were analyzed using individual t-tests. Statistical significance was set at p < .05. RESULTS: On average, the mean walking time (12.7, 18.6, 22.5 min), speed (2.6, 2.8, 3.1 mph) and distance (0.6, 0.9, 1.1 mi) increased with session number (p<.01). Walking distance was different between the sessions (p<.01). Walking speed differed between the 1st and 12th and between the 6th and 12th sessions (p<.03). The walking duration was different between the 1st and 6th and between the 1st and 12th sessions (p<.01). Heart rate while walking at an RPE of 13 was 104, 99, and 102 bpm for the 1st, 6th, and 12th session, respectively. Post-walking bout systolic BP was lower compared to pre-bout in the 1st and 6th session (p=.03) as was diastolic BP in the 12th session (p=.04). CONCLUSION: Patients significantly improved their treadmill walking time, speed and distance over the course of 12 Phase 2 cardiac rehab sessions. Clamping a cardiac rehab treadmill walking RPE at 13 may elicit similar improvements for Phase 2 patients resembling those in this study.