Introduction 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. This systematic review and meta-analysis aims to determine the effects of inspiratory muscle training (IMT) in healthy older adults given that reduced respiratory muscle strength is associated with a decline in pulmonary function, reduced physical performance, and constitutes an independent risk factor for myocardial infarction and cardiovascular mortality.

Methods A systematic literature search was conducted across four databases (Medline/Pubmed, Web of Science, Cochrane Library and CINAHL) using a search strategy consisting of both MeSH and text words including older adults, inspiratory muscle training, 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. Meta-analyses were performed for maximal inspiratory pressure (PI_max) and six-minute walk distance (6MWD) using a random-effects model with change scores to obtain effect sizes reported as standard mean differences. Pearson’s correlation analysis was performed to determine the association between baseline PI_max and change in PI_max following IMT within included studies.

Results Seven studies provided mean change scores for inspiratory muscle strength and 3 studies for functional capacity. A significant improvement was found for PI_max following training (n=7, 3.03 [2.44, 3.61], p≤0.00001) but not for 6MWD (n=3, 2.42 [-1.28, 6.12], p=0.20; figure 1). The average increase in PI_max was 26.3±4.9 cmH₂O within the experimental groups compared to a non-significant average change of 3.7± 4.1 cmH₂O within the control groups. There was no significant correlation between baseline PI_max and post-intervention change in PI_max values (n=7, r=0.342, p=0.453).

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Abstract P79 Figure 1

Mean difference (95% CI) from baseline of the effect of inspiratory muscle training on inspiratory muscle strength (measured by maximal inspiratory pressure; n=7) and six-minute walk test distance (n=3) compared to control

Discussion This study suggests that IMT is beneficial in terms of improving inspiratory muscle strength in older adults without a long-term condition. IMT was also found to be beneficial 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.