Inspiratory Muscle Strength Training May Improve Cardiopulmonary Pressures in Pulmonary Hypertension: A Case Study

Pulmonary hypertension (PH) is a progressive condition characterized by elevated mean pulmonary arterial pressures (mPAP; mPAP >20mmHg). If left untreated, PH can progress to right heart failure and premature death. While pharmacological treatment is currently the primary means of management, lifestyle interventions are increasingly recognized as helpful adjuvant strategies for PH symptom management. Inspiratory muscle strength training (IMST) has emerged as a potential therapeutic strategy to reduce common PH symptoms such as dyspnea, exercise intolerance, and respiratory muscle weakness. However, no studies have assessed the effects of an IMST intervention on central cardiopulmonary pressures or hemodynamics in PH patients. The purpose of this study was to evaluate the feasibility and effects of four-weeks of IMST (30 resisted efforts, 5 days/week, 50-55% maximal inspiratory pressure PImax) in a 41-year-old female patient with severe idiopathic pulmonary arterial hypertension. We hypothesized the training would be well-tolerated and coupled with improvements in invasive cardiopulmonary hemodynamics, respiratory muscle strength (i.e., PImax), and functional capacity. Methods: Invasive cardiopulmonary testing with right heart catheterization (RHC) during rest and hemodynamic provocation (i.e., passive leg raise) was conducted as part of her standard of care five months pre-IMST and again immediately post-IMST. During RHC, we assessed cardiopulmonary pressures, cardiac output (CO) determined via direct Fick, blood oxygen content, and peripheral pulse oximetry. Further, we evaluated PImax, spirometry, grip strength, blood pressure, six-minute walk distance (6MWT) pre- and post IMST. The participant reported daily sleep and physical activity, which were averaged weekly. Results: The participant completed 18 of the 20 prescribed IMST sessions (55% PImax; 48 cmH 2 O) at home with weekly virtual supervision. Post IMST, we noted pre to post reductions in resting mPAP (i.e., 55 vs. 47 mmHg), pulmonary capillary wedge pressure (16 vs. 12 mmHg), right atrial pressure (14 vs. 11 mmHg), and superior vena cava pressure (15 vs. 8 mmHg). We noted similar declines in mPAP during the hemodynamic provocation test (58 vs. 49 mmHg). We report pre-post improvements in pulmonary arterial resting blood oxygen saturation (i.e., SaO 2 , 70 to 77%) and peripheral pulse oximetry (SaO 2 , 89 to 93%). The participant’s inspiratory strength improved post IMST (i.e., -87 to -95 cmH 2 O) as did sleep duration (+1.8 hr/night) and physical activity (+240 min/week). Conversely, we saw no change in cardiac output (5.71 vs 6.02 L/min), systemic blood pressure (105/68 vs. 103/71), spirometry (FEV1/FVC: 75.2 vs. 76.7%), grip strength (Dominant: 27 vs. 28 kg), or performance on the 6MWT (461 vs. 464 m). Conclusion: These preliminary findings highlight improvements in cardiopulmonary pressures during rest and hemodynamic provocation following 4-weeks of time-efficient, moderate intensity IMST. Funding: This research was supported by the National Institutes of Health T32 training grant (T32HL007249) to J.L.M. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.