Does functional inspiratory muscle training improve exercise-based rehabilitation outcomes among individuals with obesity?

Background Functional inspiratory muscle training (FIMT) is performed during exercise. Obesity affects multiple body systems. Although exercise programs targeting multiple systems are recommended, the effects of comprehensive programs including respiratory muscle training in obesity remain insufficiently investigated. A new approach, FIMT, may offer a comprehensive program in obesity management. Purpose This study is the first aimed to investigate the effects of FIMT on cardiometabolic markers, body composition, peripheral muscle strength, functional capacity, pulmonary function, dynamic ventilatory responses, respiratory muscle performance (muscle strength and endurance) and physical activity in individuals with obesity. Methods 51 individuals with obesity were randomized to three groups:Aerobic and Resistance Exercise Group (AREG, n=17), FIMT Group (FIMTG, n=17), and Control Group (CG, n=17). Exercises were conducted under supervision for 60 minutes, 3 times a week for 10 weeks. AREG performed combined aerobic and resistance exercise program. FIMTG performed the same combined program as AREG and also IMT. In this group, for the first 3 weeks, IMT applied in isolation, and from week 4 IMT performed during aerobic exercise, forming the FIMT protocol. CG received a single verbal briefing on physical activity. Before and after exercise, cardiometabolic markers (glucose and lipid profile) were assessed with laboratory analysis, body composition with bioelectrical impedance analysis, peripheral muscle strength (handgrip and quadriceps muscle) with a dynamometer, functional capacity with a 6-minute walk test, respiratory function with a spirometer, respiratory muscle strength with an mouth pressure meter, respiratory muscle endurance with an IMT device, and physical activity level using a wearable activity monitor. Results The demographic and clinical characteristics of the participants are presented in Table 1. Improvements in cardiometabolic markers, body composition, peripheral muscle strength, functional capacity, and physical activity level were similar in AREG and FIMTG (p>0.05). FIMTG was superior to the other groups in terms of dynamic ventilatory responses (peak ventilation [VEpeak], peak breathing reserve [BRpeak]) (p=0.002, p=0.018), pulmonary function (peak expiratory flow [PEF] and forced expiratory flow 25-75% [FEF25-75%]) (p=0.013 and p=0.001; p=0.013 and p=0.016), respiratory muscle performance (maximum inspiratory pressure [MIP],MIP%,respiratory muscle endurance) (p=0.004 and p<0.001; p=0.023 and p<0.001; p=0.012 and p<0.001). Conclusion Aerobic-resistance exercises and combination of FIMT with resistance exercises provided similar improvements in cardiometabolic outcomes and physical performance. FIMT showed superiority in ventilatory responses and respiratory muscle performance. FIMT may be preferred as a feasible, time-efficient and preventive rehabilitation approach for obesity, even in the absence of respiratory impairment.