Efficacy of inspiratory muscle training as a practical and minimally intrusive technique to aid functional fitness among adults with obesity

Objective To examine the efficacy of inspiratory muscle training (IMT) as a non-intrusive and practical intervention to stimulate improved functional fitness in adults with obesity. As excess adiposity of the chest impedes the mechanics of breathing, targeted re-training of the inspiratory muscles may ameliorate sensations of breathlessness, improve physical performance and lead to greater engagement in physical activity. Methods Sixty seven adults (BMI = 36 ± 6.5) were randomized into either an experimental (EXP: n = 35) or placebo (PLA: n = 32) group with both groups undertaking a 4-week IMT intervention, comprising daily use of a inspiratory resistance device set to 55% (EXP), or 10% (PLA) of maximum inspiratory effort. Results Inspiratory muscle strength was significantly improved in EXP (19.1 cmH₂0 gain; P < 0.01) but did not change in PLA. Additionally, the post training walking distance covered was significantly extended for EXP (P < 0.01), but not for PLA. Bivariate analysis demonstrated a positive association between the change (%) of performance in the walking test and BMI (r = 0.78; P < 0.01) for EXP. Conclusion The findings from this study suggest IMT provides a practical, self-administered intervention for use in a home setting. This could be a useful strategy to improve the functional fitness of obese adults and perhaps lead to better preparedness for engagement in physical activity initiatives.