Inspiratory muscle training for improving inspiratory muscle strength and functional capacity in older adults: a systematic review and meta-analysis

Background: The ageing process can result in the decrease of respiratory muscle strength and consequently increased work of breathing and associated breathlessness during activities of daily living in older adults. Objective: This systematic review and meta-analysis aims to determine the effects of inspiratory muscle training (IMT) in healthy older adults. Methods: A systematic literature search was conducted across four databases (Medline/Pubmed, Web of Science, Cochrane Library CINAHL) using a search strategy consisting of both MeSH and text words including older adults, IMT and functional capacity. The eligibility criteria for selecting studies involved controlled trials investigating IMT via resistive or threshold loading in older adults (>60 years) without a long-term condition. Results: Seven studies provided mean change scores for inspiratory muscle pressure and three studies for functional capacity. A significant improvement was found for maximal inspiratory pressure (PImax) following training (n = 7, 3.03 [2.44, 3.61], P = <0.00001) but not for functional capacity (n = 3, 2.42 [-1.28, 6.12], P = 0.20). There was no significant correlation between baseline PImax and post-intervention change in PImax, values (n = 7, r = 0.342, P = 0.453). Conclusions: IMT can be beneficial in terms of improving inspiratory muscle strength in older adults regardless of their initial degree of inspiratory muscle weakness. Further research is required to investigate the effect of IMT on functional capacity and quality of life in older adults.