Is a single bout of exercise also a viable tool for blood pressure management in African and Asian populations? The HYPE2X trial protocol and design

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Current national and international guidelines recommend exercise as the first line treatment (class IA recommendation) for hypertension. These guidelines are based on research performed in predominantly Caucasian populations, yet the potency of exercise for lowering blood pressure (BP) is less studied in non-Caucasian populations. It is well-known that a great variability exists in the response to pharmacological antihypertensive treatments among ethnic groups. However, it is not clear whether this variability is also present regarding the BP response to exercise. The ‘Hypertension, Ethnicity and Exercise’ (HYPE²X ) trial will i) investigate whether a short bout of isometric strength or endurance exercise lowers blood pressure in African and Asian populations; ii) evaluate and compare differences in acute response to exercise between the Africans and Asians, and iii) increase our understanding on mechanisms related to blood pressure responses to exercise in these non-Caucasian populations. Methods and analyses A randomized controlled crossover trial will be conducted in 60 adults of African (n = 30; 50% female) or Asian (n = 30, 50% female) origin, ≥ 18 years. Healthy individuals with high to normal blood pressure (SBP: 130 – 139 mmHg or and DBP: 85 – 89 mmHg) or grade I hypertension (grade 1, SBP: 140 – 159 mmHg or DBP: 90 – 99 mmHg) will be recruited at outpatient clinics in Suriname between November 2020 – February 2021. Patients will complete three experimental sessions in a randomized order: a 30 minute walking/running bout at 40-60% of heart rate reserve; an isometric handgrip session at 30% of maximal handgrip strength and a sitting control session. (See Figure 1). Measurements will be performed before and immediately after each session. The primary outcome is daytime blood pressure measured by means of 24h blood pressure monitoring. Secondary outcomes include office BP, autonomic function (heart rate variability), cardiac function (left ventricle function), vascular function (pulse wave velocity and flow-mediated dilation) and the renin-angiotensin aldosterone system (plasma renin and aldosterone levels). Analyses will be performed using mixed models for repeated measures. A two-tailed p-value <0.05 will be considered statistically significant. Conclusion It is anticipated that the HYPE²X trial will contribute to a better understanding of the response of non-Caucasians to lifestyle interventions, in particular exercise therapy. Abstract Figure 1. Flowchart of the RCOT