Twelve Weeks of Combined Resistance and Aerobic Exercise Improves Cardiometabolic Biomarkers and Enhances Red Blood Cell Hemorheological Function in Obese Older Men: A Randomized Controlled Trial.

Sung-Woo Kim,Won-Sang Jung,Wonil Park,Hun-Young Park

doi:10.3390/ijerph16245020

Abstract

The present study examined the effect of a 12-week combined resistance and aerobic exercise training program on cardiometabolic biomarkers and red blood cell (RBC) hemorheological function in 20 obese older men (mean age: 68.8 ± 0.9 years). Subjects were randomly divided into two groups (exercise intervention [EXP; n = 10] and control [CON; n = 10]). The EXP subjects performed resistance and aerobic exercise training program three times per week for 12 weeks, and the CON subjects maintained their regular lifestyle during the intervention period. Body composition was estimated using bioelectrical impedance analysis equipment. Cardiometabolic biomarkers (glucose, insulin, homeostasis model assessment-estimated insulin resistance (HOMA-IR), HOMA β-cell function, and leptin) and RBC hemorheological parameters (RBC deformability and aggregation) were analyzed. Percent body fat decreased significantly in the EXP group during the intervention period but increased significantly in the CON group. Insulin increased significantly in the CON group over the 12-week period and both insulin and HOMA-IR were significantly higher in the CON group than in the EXP group at post-test. RBC deformability (RBC EI_3Pa) and aggregation (RBC AI_3Pa) improved significantly only in the EXP group. The present study suggests that combined exercise training can be useful for improving cardiometabolic biomarkers and RBC hemorheological parameters in obese older men and may help prevent metabolic syndrome and cardiovascular diseases.

Highlights

Red blood cell (RBC) aggregation is a reversible structure that consists of three-dimensional layers of RBCs known as “rouleaux” [1]
This study aimed to examine the effects of combined resistance and aerobic exercise on physiological parameters related to body composition, cardiometabolic biomarkers, and RBC hemorheological function in obese older men
Subjects with the following conditions were excluded from the study: those with any chronic diseases that were not under control (e.g., Alzheimer disease, dementia, arthritis, asthma, diabetes, and epilepsy), those who had undergone retinal laser treatment, those who had a history of acute myocardial infarction, those who had undergone joint replacement or suffered from fracture of the lower limb within the previous six months, and those who showed severe cognitive disturbance

Summary

Introduction

Red blood cell (RBC) aggregation is a reversible structure that consists of three-dimensional layers of RBCs known as “rouleaux” [1]. The effect of RBC aggregation on vessel resistance, tissue perfusion, and blood flow depends on the vascular area where the RBC aggregation flows [1]. RBC aggregates are typically formed in regions with low shear rates in veins. Increased RBC aggregation can lead to a rapid increase in blood viscosity in these areas. RBC deformability is another important factor that influences blood viscosity; it depends on various determinants such as membrane viscoelasticity, internal viscosity, and the surface-area-to-volume ratio [2]. Rigid RBCs are less aggregated than deformable RBCs at low shear rates [1]. At very low shear rates, the loss of RBC

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