The effects of muscle strengthening training combined with aerobic training versus aerobic training alone on cardiovascular disease risk factors in coronary artery disease: a systematic review
Authors: Terada T , Thomas A , Wei R , Visintini S , Noda T , Pap R , Reed J L 
Published: June 2024

Abstract

Background
Aerobic training reduces the risk of secondary cardiovascular events and mortality in patients with coronary artery disease (CAD). While the long-term effects of aerobic interval training (AIT) are less clear, AIT has been shown to elicit similar or superior improvements in risk factors associated with secondary cardiovascular events compared to continuous aerobic training. Current guidelines recommend performing muscle strengthening training in addition to aerobic training for enhanced cardiovascular care in patients with CAD. However, it remains unclear whether muscle strengthening training combined with aerobic training (hereafter referred to as combined training) has additional effects on cardiovascular disease risk factors in patients with CAD. It is also unknown if muscle strengthening training combined with AIT has greater effects on cardiovascular disease risk factors compared to AIT alone in patients with CAD.

Purpose
To systematically review the effects of combined training compared to aerobic training alone on cardiovascular disease risk factors in patients with CAD. The secondary purpose was to examine the effects muscle strengthening training combined with AIT on cardiovascular disease risk factors compared to AIT alone.

Methods
MEDLINE, Embase, CINAHL, SportDiscus, Scopus, and trial registries were searched for randomized trials comparing the effects of ≥4 weeks of combined training and aerobic training alone on at least one of the following outcomes: cardiorespiratory fitness, body mass, body mass index (BMI), percent body fat, waist-to-hip ratio, blood pressure, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), total cholesterol, fasting glucose, glycated hemoglobin A1C (A1C), insulin concentration or sensitivity, in patients with CAD.

Results
Of 9336 studies screened, 16 studies (N=710 patients with CAD) were included. Combined training was more effective in increasing fat-free mass (mean difference [MD] = 0.8 kg, 95% confidence interval [CI]: 0.4 to 1.1 kg, p&lt;0.001) and reducing percent body fat (MD = -2.2 %, 95% CI: -3.6 to -0.8 %, p=0.002) measured by dual-energy x-ray absorptiometry compared to aerobic training alone. Four of these 16 studies examined the effects of muscle strengthening training combined with AIT compared to AIT alone. There were no differences between the groups. Sensitivity analyses on studies with matched aerobic training volume between combined training and aerobic training alone (i.e., excluding studies with reduced aerobic training in the combined training group to add muscle strengthening training) showed consistent findings.

Conclusion
Adding muscle strengthening training to aerobic training improved the body composition of patients with CAD more than aerobic training alone. However, changes in the other cardiovascular disease risk factors were similar between combined and aerobic training alone.