Pulmonary arterial hypertension is a rare condition characterised by high blood pressure in the lungs and results in breathlessness and reduced exercise capacity for patients. Previous research has shown weakness in respiratory muscles in these patients that may contribute towards their symptoms. Despite advances in medical therapy, the condition still results in a significant symptom burden.

Inspiratory muscle training is a non-invasive intervention involving a device that provides resistance to the muscles of inspiration and increases their strength.

This study will investigate the benefit of inspiratory muscle training in patients with pulmonary arterial hypertension who are stable on medical therapy for three months. This will be performed as an outpatient and they will then be reviewed following this with assessment of exercise capacity, breathing capacity (spirometry), quality of life, and assessment of neural respiratory drive (the signals from the brain to the muscles controlling breathing).

The study will be based at the Golden Jubilee National Hospital and patients will be recruited from outpatients who are already under the care of the Scottish Pulmonary Vascular Unit.

Inclusion Criteria:

• diagnosed by pulmonary hypertension specialist with precapillary pulmonary hypertension
• able to give consent
• stable on medical therapy for at least 3 months

Exclusion Criteria:

• significant contribution to pulmonary hypertension from lung disease
• pregnant