Objective
To explore the incremental dose-response effect of aerobic exercise-based cardiac rehabilitation programs (ExCRP) on cardiorespiratory fitness in comparison to non-exercise controls among people with coronary heart disease (CHD).
Review Methods
Medline, CINAHL, Cochrane, SCOPUS, and SPORTDiscus were searched from January 1, 2000 until December 4, 2023. Articles were eligible for selection if they satisfied the following criteria: randomized controlled studies assessing change in cardiorespiratory fitness among people with CHD in non-exercise and aerobic intervention groups, established peak oxygen uptake via cardiopulmonary exercise test, minimum of 4-week program duration, and reported frequency, intensity, and duration of prescribed exercise. The study was prospectively registered (PROSPERO ID: CRD42021274924).
Summary
Thirty-three studies, including 1901 participants were included in the continuous dose-analysis. A significant difference in cardiorespiratory fitness was identified between ExCRP and non-exercise control that favored exercise by 3.4 (3.0-3.9) mL·kg -1 ·min -1 . No difference existed between interval and continuous training when matched for exercise dose. Dose-response analyses identified a significant increase in cardiorespiratory fitness (3.4 [2.9-5.5] mL·kg -1 ·min -1 ) associated with program completion, with no additional benefit related to increased exercise dose. When compared to non-exercise control, participating in ExCRP with a minimum total program intervention dose of 2194 metabolic equivalent minutes significantly improves cardiorespiratory fitness. However, no additional benefit was discernible from higher exercise doses. Although the recommended dose for ExCRP augments medical treatment and is sufficient to improve cardiorespiratory fitness, it is likely that the narrow range in prescribed exercise dose and variations in the fidelity of exercise interventions limit interpretation.