Does Exercise Intensity Differ Between Exercise Equipment In Cardiac Rehabilitation?

PURPOSE: Exercise intensity in cardiac rehabilitation (CR) predicts fitness gains in CR, but little is known about how exercise modality impacts exercise intensity and how/if the use of a target heart rate (THR) modulates exercise intensity. We hypothesized that seated modalities would have lower exercise intensity as measured by exercise heart rate (HR). METHODS: As part of a randomized trial (NCT05925634) testing the difference between ratings of perceived exertion (RPE) and THR on fitness gains in CR, we assessed the impact of exercise mode (treadmill, upright bike, recumbent bike, and seated dual-action elliptical/stepper) and exercise prescription method (RPE vs THR) on exercise intensity. RPE was prescribed at 3-4 on the Borg 1-10 scale and THR was prescribed from a maximal exercise test (60%-85% of HR reserve). Continuous HR was measured every other CR session using an upper arm HR monitor. Exercise intensity was defined by proportion of exercise time (%) above HR thresholds: Resting HR +30 and Resting HR +40. We then analyzed exercise intensity by modality for both groups. RESULTS: We enrolled 24 patients (66% men, 69 years, 83% white) who completed 29 ± 13 sessions, and had 701 total observations. Exercise intensity was higher in the THR vs. RPE group for all modalities except recumbent bicycle. (see Table) Exercise intensity was lower on seated modality, with a more notable effect in the RPE group. CONCLUSION: Patients in THR group had a higher exercise intensity regardless of modality. Seated dual-action elliptical/stepper produced the lowest exercise intensity in all groups, with more notable negative effects in the RPE group. These finding highlight the importance of a THR to guide exercise in CR. Percent time above HR threshold - Modality Group N Obs > = HR + 30 p-value* > = restHR + 40 p-value* Seated Stepper RPE 60 57.8 0.004 27.3 0.0004 Seated Stepper THR 103 83.1 49.4 Recumbent Bike RPE 27 79.1 0.83 32.4 0.26 Recumbent Bike THR 127 79 43.1 Treadmill RPE 75 65.5 0.005 33.4 0.001 Treadmill THR 172 80.7 48.5 Upright Bike RPE 48 57.4 0.0001 39.9 0.002 Upright Bike THR 89 89.5 62.7 Supported by: Research reported in this abstract was supported by National Institute of Aging of the National Institutes of Health under award number R01AG077179.This study is registered with ClinicalTrials.gov as #NCT05925634