Six-week inspiratory resistance training ameliorates endurance performance but does not affect obesity-related metabolic biomarkers in obese adults: A randomized controlled trial

This investigation examined the effects of a six-week inspiratory resistance training (IRT) on metabolic health biomarkers, pulmonary function, and endurance in obese individuals. Twenty-eight obese adults (BMI > 27 kg/m² Taiwan obesity criteria) were randomly assigned to either IRT (IRT; N = 16) or sham control (PLA; N = 12). The training parameters (twice/day; 3 days/week; 30 breaths/section; IRT: 55% PImax [maximal inspiratory pressure], PLA: 10% PImax) were identical. The endurance, pulmonary function, and blood lipid profiles were measured before/after intervention. After training, the PImax in IRT was greater than in PLA (+49.6%, p < .001), and the 6-minute walking test (6MWT) performance in IRT was greater than in PLA (+12.9%, p = 0.001). However, there were no differences in pulmonary function (FVC, FEV₁, or FEV₁/FVC) and lipid profiles between groups. Our results demonstrate that a six-week progressively-programmed IRT was effective to improve endurance capacity and inspiratory muscle strength in obese individuals, whereas the IRT had no effects on pulmonary function, body composition, and blood lipid profiles.