Background:Heart failure with preserved ejection fraction is a clinical syndrome characterised by reduced exercise capacity. Some evidence has shown that a simple and home-based programme of inspiratory muscle training offers promising results in terms of aerobic capacity improvement in patients with heart failure with preserved ejection fraction. This study aimed to investigate whether the baseline inspiratory muscle function predicts the changes in aerobic capacity (measured as peak oxygen uptake; peak VO₂) after a 12-week home-based programme of inspiratory muscle training in patients with heart failure with preserved ejection fraction.Methods:A total of 45 stable symptomatic patients with heart failure with preserved ejection fraction and New York Heart Association II–III received a 12-week home-based programme of inspiratory muscle training between June 2015 and December 2016. They underwent cardiopulmonary exercise testing and measurements of maximum inspiratory pressure pre and post-inspiratory muscle training. Maximum inspiratory pressure and peak VO₂were registered in both visits. Multivariate linear regression analysis was used to assess the association between changes in peak VO₂(Δ-peakVO₂) and baseline predicted maximum inspiratory pressure (pp-MIP).Results:The median (interquartile range) age was 73 (68–77) years, 47% were women and 35.6% displayed New York Heart Association III. The mean peak VO₂at baseline and Δ-peakVO₂post-training were 10.4±2.8 ml/min/kg and +2.2±1.3 ml/min/kg (+21.3%), respectively. The median (interquartile range) of pp-MIP and Δ-MIP were 71% (64–92) and 39.2 (26.7–80.4) cmH₂O, respectively. After a multivariate analysis, baseline pp-MIP was not associated with Δ-peakVO₂(β coefficient 0.005, 95% confidence interval −0.009–0.019, P=0.452).Conclusions:In symptomatic and deconditioned older patients with heart failure with preserved ejection fraction, a home-based inspiratory muscle training programme improves aerobic capacity regardless of the baseline maximum inspiratory pressure.