Objective Assess the role of exercise intensity on changes in cardiorespiratory fitness (CRF) in patients with cardiac conditions attending exercise-based cardiac rehabilitation.
Design Systematic review with meta-analysis.
Data sources MEDLINE, Embase, CINAHL, SPORTDiscus, PsycINFO and Web of Science.
Eligibility criteria for selection Studies assessing change in CRF (reported as peak oxygen uptake; V̇O2peak) in patients post myocardial infarction and revascularisation, following exercise-based cardiac rehabilitation. Studies establishing V̇O2peak via symptom-limited exercise test with ventilatory gas analysis and reported intensity of exercise during rehabilitation were included. Studies with mean ejection fraction <40% were excluded.
Results 128 studies including 13 220 patients were included. Interventions were classified as moderate, moderate-to-vigorous or vigorous intensity based on published recommendations. Moderate and moderate-to-vigorous-intensity interventions were associated with a moderate increase in relative V̇O2peak (standardised mean difference±95% CI=0.94±0.30 and 0.93±0.17, respectively), and vigorous-intensity exercise with a large increase (1.10±0.25). Moderate and vigorous-intensity interventions were associated with moderate improvements in absoluteV̇O2peak (0.63±0.34 and 0.93±0.20, respectively), whereas moderate-to-vigorous-intensity interventions elicited a large effect (1.27±0.75). Large heterogeneity among studies was observed for all analyses. Subgroup analyses yielded statistically significant, but inconsistent, improvements in CRF.
Conclusion Engagement in exercise-based cardiac rehabilitation was associated with significant improvements in both absolute and relative V̇O2peak. Although exercise of vigorous intensity produced the greatest pooled effect for change in relative V̇O2peak, differences in pooled effects between intensities could not be considered clinically meaningful.
Registration Prospero CRD42016035638.
- exercise rehabilitation
- aerobic fitness
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Contributors BLM contributed to the design of the study, literature search, data screening and extraction and risk of bias assessment; conducted all statistical analyses and managed all aspects of the manuscript preparation and submission. MJL contributed to the literature search, data screening and extraction and risk of bias assessment and contributed to the writing and editing of the manuscript. KD, GP and RGE contributed to the study design, search strategy and statistical plan and contributed to the writing and editing of the manuscript. JPB contributed to the search strategy, provided theoretical and practical expertise and contributed to the interpretation of the findings and editing of the manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement All data in this review are available in the journal in which they were published.