Aerobic Training Is Better Than Resistance Training on Cardiac Function and Autonomic Modulation in Female ob/ob Mice.

Filipe Fernandes Stoyell-Conti,Bruno Rodrigues,Jacqueline Freire Machi,Fernando dos Santos,Maria-Claudia Irigoyen,Kátia De Angelis,Michelle Sartori,Diego Mendrot Taboas Figueroa,Amanda Aparecida Ribeiro

doi:10.3389/fphys.2019.01464

Abstract

Objective: This study evaluated the effects of aerobic, resistance, and combined exercise training on cardiac function and autonomic modulation in female ob/ob mice.Methods: Four-week-old female wild type and obese (ob/ob) mice were divided into five groups (n = 8): control (WT), obese (OB) obese + aerobic training (OBA), obese + resistance training (OBR), and obese + combined training (OBC). The exercise training was performed on treadmill and/or ladder at 40–60% maximum test during 8 weeks. Cardiac function was measured using echo machine. Heart rate variability (HRV) was evaluated in the time and frequency domain.Results: OB group presented higher body weight gain (~600%), glycemia (~44%) and glucose intolerance (~150%), reduction of cardiac vagal modulation, evidenced by a lower RMMSD (~56%), total power and high frequency band, and a higher isovolumic relaxation time (IVRT) (~24%) in relation to the WT group. Aerobic and combined training led to a lower IVRT (OBA: ~14%; OBC: ~14%) and myocardial global index (OBA: ~37%; OBC: ~44%). The OBA group presented an increased in vagal indexes of HRV than the other ob/ob groups. A negative correlation was observed between the delta of aerobic exercise capacity and MPI (r = 0.45; p = 0.002) and exercise capacity and body weight gain (r = 0.39; p = 0.002).Conclusion: Only the obese females underwent to aerobic exercise training showed improvement in cardiac function and HRV. Moreover, the aerobic exercise capacity as well as a greater responsivity to aerobic exercise training is intimately associated with these improvements, reinforcing the importance of aerobic exercise training to this population.

Highlights

Obesity is an important risk factor for cardiovascular disease (CVD), such as left ventricular dysfunction, congestive heart failure, stroke, and cardiac arrhythmias
The mice were divided into wild-type sedentary group (WT; n = 8), ob/ob sedentary group (OB; n = 8), ob/ob + aerobic exercise training group (OBA; n = 8), ob/ob + resistance exercise training group (OBR; n = 8), and ob/ob combined exercise training group (OBC; n = 8)
All three groups that underwent exercise training protocol showed a lower body weight gain than the sedentary group, being the aerobic exercise training a better approach when compared to the resistance and combined exercise training (OBA: 15.3 ± 0.5; OBR: 17.8 ± 0.8; OBC: 18.3 ± 0.6 g)

Summary

Introduction

Obesity is an important risk factor for cardiovascular disease (CVD), such as left ventricular dysfunction, congestive heart failure, stroke, and cardiac arrhythmias. It is related to several cardiovascular risk factors as well as dyslipidemia, hypertension, inflammation, insulin resistance, and type 2 diabetes mellitus (Klein, 2004). More than 80% of diabetic subject present overweight or are obese (Centers for Disease Control and Prevention (CDC), 2004). The cardiovascular complications of diabetes mellitus include coronary heart disease (CHD), stroke, peripheral arterial disease, nephropathy, retinopathy, and possibly cardiomyopathy and neuropathy (Grundy et al, 1999). We showed that female adult ob/ob mice, a model of obesity and type 2 diabetes, present discrete diastolic dysfunction accompanied by autonomic disorder, which is associated with inflammation and oxidative stress (Sartori et al, 2017)

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Results

Conclusion