Feasibility study to assess the delivery of a novel isometric exercise intervention for people with high blood pressure in a healthcare setting

BACKGROUND: Hypertension affects 1:4 adults and increases the risk of CV disease. Management aims to reduce blood pressure to a level that minimizes risk; up to 50% of people don't achieve blood pressure targets often due to insufficient treatment or poor adherence. Exercise has a role to play in the management of hypertension. The impact of isometric exercise on hypertension in healthcare settings is poorly understood. METHODS: Randomized controlled open-label multicentre feasibility study of isometric exercise compared to standard care in unmedicated hypertensives. Participants received an individualised isometric wall squat prescription and performed 4 x 2-minute bouts thrice weekly for 6-months. We assessed recruitment, deliverability, attrition, adherence, and variance in blood pressure change. RESULTS: 41 participants (56 +/- 15 years), 59% women, were randomized. Isometric exercise was found to be easily deliverable to all participants. At 6-months 34% withdrew, of those who completed isometric exercise 87% of their sessions were at the correct intensity. Variance in blood pressure change was 14.4 mmHg. The study was not powered to show a difference in blood pressure between groups, however blood pressure reductions were seen in the intervention group at all study time points compared to baseline. CONCLUSIONS: The results have allowed us to calculate a sample size (n=542) for a full randomised controlled trial. The results demonstrate good acceptability and adherence rates to the treatment protocol. Our results show a signal towards a consistent systolic blood pressure reduction in the isometric exercise group compared to baseline. REGISTRATION: NCT04936022 https://classic.clinicaltrials.gov/ct2/show/NCT04936022cond=isometric+exercise&draw=2&rank=7 Registry Identifier: ISRCTN:13472393