Abstract
Postmenopausal women with obesity often show blood abnormalities and low plasma volume, which reduce aerobic capacity and raise health risks. The purpose is to compare the effects of high-intensity (HIIWT) versus moderate-intensity interval walking training (MIIWT) on body composition, plasma volume variations (PVV), hematological parameters, muscle damage, and aerobic capacity in postmenopausal women with overweight/obesity. Thirty-two postmenopausal women with overweight/obesity were randomly assigned to HIIWT (n = 11), MIIWT (n = 11), or control (CON, n = 10) groups. The HIIWT and MIIWT groups performed intermittent walking at 90-110% and 60-80% of their 6-min-walk-test (6MWT) distance, respectively, four times per week for 10 weeks. Body composition, hematological and muscle damage markers, and 6MWT performance were assessed pre- and post-intervention. After ten weeks, PVV was calculated in all three groups. A significant group × time interaction was observed for body composition, erythrocytes, hemoglobin levels, hematocrit, creatine kinase (CK), lactate dehydrogenase (LDH), and 6MWT performance (p < 0.05). Both the HIIWT and MIIWT groups showed significant reductions in body mass, body fat, waist circumference (p < 0.05), and erythrocyte count (p = 0.010 and 0.028, respectively). Only the HIIWT group showed significant reductions in hemoglobin (p < 0.001), hematocrit (p = 0.005), CK (p = 0.002), and LDH (p = 0.009), along with a significant increase in 6MWT-performance (p = 0.002). The HIIWT group demonstrated a significantly greater increase in PVV compared to both MIIWT (p = 0.018) and CON (p < 0.001) groups. HIIWT induced superior improvements in body composition, aerobic capacity, plasma volume, and hematological and muscle-damage markers compared to MIIWT. HIIWT represents a practical strategy for improving health outcomes in postmenopausal women with overweight/obesity.