What is the clinical evidence from this study?

Study design: RCT. Population: Heart failure with LVEF <50% (n=65). Intervention: Inspiratory muscle training (IMT) added to aerobic and resistance training (ARIS strategy) vs. Standard aerobic and resistance training (60 min/session). Primary outcome: Change in Kansas City Cardiomyopathy Questionnaire (KCCQ) Overall Summary Score (Mean difference +6.3 points, p=0.006).

What question did this study set out to answer?

To investigate the impact of inspiratory muscle training combined with standard rehabilitation on heart failure patients with LVEF < 50%.

April 23, 2026Open Access

Inspiratory muscle training as an adjunct to standard cardiac rehabilitation in patients with LVEF < 50%: a randomized controlled trial

Q: What are the key findings of this study?

Adding inspiratory muscle training to standard rehabilitation improved the KCCQ Overall Summary Score by 6.3 points compared to standard training alone in heart failure patients with LVEF <50%.

Q: What question did this study set out to answer?

To investigate the impact of inspiratory muscle training combined with standard rehabilitation on heart failure patients with LVEF < 50%.

Key Result

Adding inspiratory muscle training to standard rehabilitation improved the KCCQ Overall Summary Score by 6.3 points compared to standard training alone in heart failure patients with LVEF <50%.

Key Points

To investigate the impact of inspiratory muscle training combined with standard rehabilitation on heart failure patients with LVEF < 50%.
Randomized 65 heart failure patients with LVEF < 50% to two groups: standard training and standard training plus inspiratory muscle training.
Both groups underwent 36 sessions over 12 weeks, with data analyzed using intention-to-treat principles.
Primary outcomes included changes in quality of life (KCCQ score) and functional capacity (6-minute walk distance).
The inspiratory muscle training group showed a significant improvement in the KCCQ score (+6.3 points; P = 0.006).
There were notable increases in 6-minute walk distance (+33.9 m; P = 0.016) and maximal inspiratory pressure (+2.0 kPa; P < 0.001).
No significant changes were found in left ventricular ejection fraction or left ventricular end-diastolic volume between groups.

Study Design

Type

RCT (n=65)

Blinding

PROBE (Open-label, blinded endpoint)

Randomization

1:1

Multicenter

Structured PICO

Does adding inspiratory muscle training to standard aerobic and resistance training improve quality of life and functional capacity in patients with heart failure and LVEF < 50%?

Population

65 adults (18-80 years) with stable chronic heart failure (LVEF < 50%, NYHA class II-III), mean age ~55, ~81% male, based in China. Key inclusion: symptom stability ≥3 months, physically able to undergo exercise testing and training.

Intervention

Aerobic and resistance training plus inspiratory muscle training (ARIS strategy; 90 min/session). Prescribed as 36 sessions (3 sessions/week for 12 weeks). The 30-minute respiratory module included 20 minutes of inspiratory muscle training using a portable resistance device (progressive loading from 30% to 60% of maximal inspiratory pressure) and 10 minutes of breathing pattern retraining.

Comparator

Standard aerobic and resistance training (AR group; 60 min/session). Prescribed as 36 sessions (3 sessions/week for 12 weeks). Included 5 min warm-up, 30-40 min aerobic training, 20-30 min resistance training, and 5 min cool-down.

Outcome

Change in the Kansas City Cardiomyopathy Questionnaire (KCCQ) Overall Summary Score at 12 weeks post-intervention.patient reported

Main Result

Effect estimate: Mean difference +6.3 points

p-value: p=0.006

Limitations

Single-center study design
Participants and supervising therapists could not be blinded to the exercise intervention
Full protocol adherence (completing all 36 sessions) was only achieved by 53.1% to 57.6% of patients
Adequately powered studies are needed to confirm efficacy in the HFmrEF subgroup

Abstract

Impaired inspiratory muscle strength is prevalent in heart failure (HF). Despite standard aerobic and resistance training, patients often experience residual exercise intolerance. Adding inspiratory muscle training (IMT) appears promising, but its aprecise additive value remains unclear, particularly in contemporary cohorts with LVEF < 50%. We randomized 65 HF patients (LVEF < 50%) to standard aerobic and resistance training (AR group, n = 32; 60 min/session) or AR plus IMT (ARIS strategy, n = 33; 90 min/session). Both protocols prescribed 36 sessions (3 sessions/week for 12 weeks). The primary outcome was the change in the Kansas City Cardiomyopathy Questionnaire (KCCQ) Overall Summary Score. Data were analyzed according to the intention-to-treat (ITT) principle. Full completion of all 36 prescribed sessions was achieved by 53.1% (AR) and 57.6% (ARIS) of patients, yielding an actual time-adjusted training density of 2.38 and 2.53 sessions/week, respectively. In the primary outcome analysis, the ARIS strategy demonstrated greater KCCQ Overall Summary Score improvement (between-group difference: +6.3 points; P = 0.006), exceeding the minimal clinically important difference (MCID) of 5 points. The ARIS strategy also yielded significantly greater increases in 6-minute walk distance (+ 33.9 m; P = 0.016) and maximal inspiratory pressure (+ 2.0 kPa; P < 0.001). Regarding cardiac structure, no significant between-group differences were observed for changes in LVEF (P = 0.818) or left ventricular end-diastolic volume (LVEDV) (P = 0.990). In HF patients (LVEF < 50%), the extended multimodality ARIS strategy provides clinically significant improvements in quality of life and functional capacity compared to standard training. These incremental benefits likely stem from the combined addition of IMT and higher exercise volume, occurring without significant between-group differences in macro-structural cardiac remodeling. Adequately powered studies are needed to confirm efficacy in the HFmrEF subgroup. Chinese Clinical Trial Registry ChiCTR2500108124. Retrospectively registered on 25 August 2025.

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