Exercise and grape extract intake (i.e., polyphenol-rich product) can independently improve blood pressure and endothelial function in prehypertensive individuals. Nevertheless, their combined effects remain unexplored. Furthermore, since the biological pathways targeted by both interventions are similar, they could overlap and be amplified by one another, promoting additive or synergistic effects. Animal model studies have reported that a grape seed extract intake prevents exercise-induced oxidative stress, which could improve vascular dysfunction. Furthermore, as previously reported, a single dose of grape seed extract reduces blood pressure, peripheral vasoconstriction, and heart stress, enhancing O2 delivery during exercise in prehypertensive males. These effects may be partly due to endothelium-dependent vasodilation enhancement. Therefore, it is necessary to understand the potential impact of exercise and grape extract on blood pressure and vascular function in prehypertensive individuals.

Inclusion Criteria:

• Sedentary individuals (<120 min·wk-1 of moderate-intensity activity assessed by 7-d IPAQ).
• Aged 25-70 years and BMI 18-40 kg/m2.
• Elevated BP (i.e., prehypertensive; systolic and diastolic BP between 120-139 and/or 80-89 mmHg, respectively)

Exclusion Criteria:

• Weight instability (>5kg change in body mass over last 6 months)
• Pregnant or lactating
• Changes in physical activity over the last 3 months and planning on physical activity, or diet throughout the intervention.
• Untreated cardiovascular or renal disease, peripheral vascular disease, hypertension, and any disease associated with exercise intolerance.
• Currently taking dietary supplements that influence the cardiovascular response (e.g., polyphenols, omega-3 fatty acids, Magnesium, nitrates, L-arginine, red ginseng, natto, ginkgo, CoQ10) or used in the last month.
• Current or recent use (within the past 6 months) of tobacco or nicotine-containing products, or illicit drugs.
• Any medical condition or medication that could introduce bias into the study (e.g. neurological disorders)

Several strategies will be used to ensure the double-blind design. First, both formulations will contain identical inert excipients (such as microcrystalline cellulose, magnesium salts of fatty acids, or silicon dioxide) to ensure indistinguishable taste, smell, and texture. Furthermore, the capsules will be identical in color, size, and shape, using standard materials that prevent distinction of the contents. Both formulations will be non-calorie flavoured, avoiding taste differences, especially if the capsules are accidentally chewed. Furthermore, encapsulation will be performed by a specialized laboratory, such as Alvinesa Natural Ingredients, ensuring a consistent preparation. Finally, the capsules will be distributed in identical packaging without distinctive markings that could compromise the double-blind design.