The optimal treatment duration for inspiratory muscle strengthening exercises in stroke patients: a double-blinded randomized controlled trial.

Background: Little is known about the ideal duration of inspiratory muscle training in stroke patients.

Objective: The aim of this study was to assess the effects of short-term and long-term inspiratory muscle strengthening exercises in stroke patients.

Methods: This study was a prospective, double-blind, randomized controlled trial involving 50 stroke patients. Based on baseline maximum inspiratory pressure (MIP) values, participants were divided into two strata: those with severely weak inspiratory muscle (stratum A) and those with moderately weak inspiratory muscle (stratum B). Within each stratum, individuals were randomly assigned to either the 4-week exercise group, the 8-week exercise group, or the sham group. The exercise groups underwent inspiratory muscle strengthening exercises. The MIP, 6-minute walk test (6MWT), and the Nottingham Extended Activities of Daily Living (NEADL) Index were assessed at baseline, 8, 12, and 24 weeks.

Results: Subjects in Stratum A exhibited notably greater improvement after 8 weeks of training compared to those in Stratum B. Furthermore, both Stratums displayed significantly greater improvement following 8 weeks of training compared to sham training. In Stratum B cases, a significantly higher level of improvement was noted with the 4-week training in comparison to the sham training. A significant increase in NEADL index and 6MWT score was observed during the 24-week follow-up period.

Conclusion: For individuals with moderately weak inspiratory muscle strength, a 4-week exercise program proves sufficient in enhancing inspiratory muscle strength, walking capacity, and daily life activities. However, individuals with severely weak inspiratory muscle strength benefit more from an 8-week treatment.