Effects of inspiratory muscle training on functional fitness in obese and overweight adults: A systematic review of randomised control trials

Background: Obesity is a chronic metabolic disorder that affects the cardiopulmonary system. Its management, mainly, focuses on weight loss programmes without incorporating respiratory management. Threshold inspiratory muscle trainers (IMT) was used to strengthen inspiratory muscles and improve functional exercise capacity in obese and overweight individuals. Objective: To investigate the effectiveness of IMT on functional fitness in overweight and obese individuals. Methods: An electronic search was conducted in Scopus, PubMed, Web of Science, Dimension, Medline, and Open Alex database. The review included studies of randomised controlled trials (RCTs), which were conducted for the last 20 years on healthy adults with obesity, and the studies investigating the effects of IMT on multiple parameters. The revised Cochrane risk of bias tool (RoB 2.0) was employed to assess the methodological quality of the included studies. Results: The initial search yielded 832 studies. Ultimately, five randomised control trials with three to four measurement outcomes were included. Inspiratory muscle strength and functional capacity outcomes were measured, with pre-and post-IMT intervention assessments performed. Results suggest that IMT improves functional capacity (6MWT) and inspiratory muscle strength without a significant difference in the pulmonary function test. Conclusion: IMT improves inspiratory muscle strength and functional capacity in obese and overweight adult individuals. Healthcare professionals should consider including IMT to any prescribed rehabilitation program particularly for those with obese and overweight.