Exercise Intensity in Patients with Cardiovascular Diseases: Systematic Review with Meta-Analysis

Catarina Gonçalves; Armando Raimundo; Ana Abreu; Jorge Bravo

doi:10.3390/ijerph18073574

March 30, 2021International Journal of Environmental Research and Public HealthOpen Access

Exercise Intensity in Patients with Cardiovascular Diseases: Systematic Review with Meta-Analysis

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Why the study?

Although exercise-induced improvements in VO2peak during cardiac rehabilitation are well documented, the optimal exercise intensity remains doubtful.

Does higher exercise intensity improve cardiorespiratory fitness in patients with cardiovascular diseases following cardiac rehabilitation?

Structured PICO

Does higher exercise intensity improve cardiorespiratory fitness in patients with cardiovascular diseases following cardiac rehabilitation?

P

Population

Patients with cardiovascular diseases (CVDs) following cardiac rehabilitation (16 RCTs)

I

Intervention

Exercise interventions of varying intensities (moderate, moderate-to-vigorous, vigorous) conducted for 6-12 weeks

C

Comparator

Control group

O

Outcome

Cardiorespiratory fitness (VO2peak or VO2 at anaerobic threshold)surrogate

Moderate-to-vigorous and vigorous-intensity exercise interventions for 6-12 weeks are highly effective at improving cardiorespiratory fitness in patients with cardiovascular diseases.

Limitations

High heterogeneity in moderate-to-vigorous and vigorous-intensity interventions (I2 values of 91% and 95%)

Implication

Higher-intensity exercise may be prioritized post-cardiac rehab to maximize VO2peak; extends RCT evidence for intensity-dependent CRF gains in CVD.

Abstract

Exercise-induced improvements in the VO2peak of cardiac rehabilitation participants are well documented. However, optimal exercise intensity remains doubtful. This study aimed to identify the optimal exercise intensity and program length to improve VO2peak in patients with cardiovascular diseases (CVDs) following cardiac rehabilitation. Randomized controlled trials (RCTs) included a control group and at least one exercise group. RCTs assessed cardiorespiratory fitness (CRF) changes resulting from exercise interventions and reported exercise intensity, risk ratio, and confidence intervals (CIs). The primary outcome was CRF (VO2peak or VO2 at anaerobic threshold). Two hundred and twenty-one studies were found from the initial search (CENTRAL, MEDLINE, CINAHL and SPORTDiscus). Following inclusion criteria, 16 RCTs were considered. Meta-regression analyses revealed that VO2peak significantly increased in all intensity categories. Moderate-intensity interventions were associated with a moderate increase in relative VO2peak (SMD = 0.71 mL-kg−1-min−1; 95% CI = [0.27–1.15]; p = 0.001) with moderate heterogeneity (I2 = 45%). Moderate-to-vigorous-intensity and vigorous-intensity interventions were associated with a large increase in relative VO2peak (SMD = 1.84 mL-kg−1-min−1; 95% CI = [1.18–2.50], p < 0.001 and SMD = 1.80 mL-kg−1-min−1; 95% CI = [0.82–2.78] p = 0.001, respectively), and were also highly heterogeneous with I2 values of 91% and 95% (p < 0.001), respectively. Moderate-to-vigorous and vigorous-intensity interventions, conducted for 6–12 weeks, were more effective at improving CVD patients’ CRF.