Smartphone App-guided Inspiratory Muscle Strength Training for Lowering Systolic Blood Pressure

Having above-normal blood pressure, i.e., ≥120 mmHg systolic blood pressure (SBP) and/or ≥80 mmHg diastolic blood pressure (DBP), increases risk of developing cardiovascular diseases, cognitive decline/dementia, chronic kidney disease, and other chronic health problems. Approximately 60% of all US adults have above-normal BP, primarily driven by above-normal SBP. Currently, above-normal SBP is the single largest modifiable risk factor for cardiovascular mortality in the United States. Thus, developing novel strategies for lowering SBP is an urgent public health and biomedical research priority. Guidelines emphasize regular aerobic exercise as a first-line intervention for all stages of above-normal systolic blood pressure (SBP). Current guidelines call for ≥150 minutes of aerobic activity per week. However, only \~50% of US adults meet these aerobic exercise guidelines. The greatest reported barrier to achieving aerobic exercise guidelines is lack of time. High-resistance inspiratory muscle strength training (IMST) is a time-efficient (5 minutes per session) lifestyle intervention consisting of 30 inspiratory maneuvers performed against a high resistance. Preliminary data suggest 6-weeks of IMST performed 6 days/week reduces SBP by 9 mmHg in adults with above-normal SBP (i.e., greater than 120 mmHg) at baseline. Importantly, this reduction in SBP is equal to or greater than the reduction in blood pressure typically achieved with time- and effort-intensive healthy lifestyle strategies like conventional aerobic exercise. The investigators hope utilizing a smartphone app to guide IMST will promote the translation of IMST for widespread use and improving public health. The investigators will conduct a randomized, controlled, single-blind, parallel group design clinical trial to assess the efficacy of 6-weeks of IMST (55%-75% maximal inspiratory pressure) delivered in the research clinic by the study investigators vs. IMST delivered entirely via a smartphone app without investigator involvement, for lowering resting and home SBP in adults aged 18 years and older with above-normal SBP (120-160 mmHg) at baseline. The investigators will also assess the effect of IMST on endothelial function, large-elastic artery stiffness, and potential mechanisms of action.