Effect of high-intensity resistance training (HIRT) on pulmonary and systemic immune responses in older adults with metabolic syndrome

<bold>Background:</bold> Metabolic syndrome (MS) prevalence is rising among older adults, impacting respiratory and immune systems. HIRT may mitigate MS effects, but its impact on older adults with MS remains unclear. <bold>Aim:</bold> To assess whether bi-weekly HIRT improves functional capacity, pulmonary function/mechanics, and immune responses in older adults with MS. <bold>Methods:</bold> 46 older adults (66±5 years) with MS were allocated into Intervention Group (IG, n=23)- bi-weekly HIRT (80-90% 1RM for 5 weeks), and Control Group (CG, n=23). Assessments included body composition, functional capacity, lung function and mechanics, and inflammatory markers. Results: No differences were observed in CG before and after 5 weeks. The IG reduced waist circumference and waist-to-hip ratio (p=0.01), but not body weight. HIRT improved flexibility, marching performance, 6-minute walking test distance, anaerobic capacity, grip strength, and maximal inspiratory/expiratory pressure and peripheral muscle strength (p<0.01). Lung mechanics improved (R5Hz, R20Hz, Z5Hz, and X5Hz, p<0.05), but not lung function. HIRT increased anti-fibrotic/anti-inflammatory molecules as adiponectin (p<0.05) in breath condensate (BC) and klotho, relaxin-1, relaxin-3, IL-1ra, and IL-10 (p<0.05) in both BC and serum, while decreasing pro-inflammatory molecules as leptin in serum (p<0.05), IL-6, TNF-α in BC (p<0.05) and serum (p<0.05), and increasing the VEGF (p<0.05) in serum. Total leukocyte, neutrophil, lymphocyte, and monocyte counts decreased in blood (p<0.05) and in induced sputum (p<0.05). <bold>Conclusions:</bold> HIRT mitigates MS impact on respiratory, skeletal muscle, and immune responses in older adults.