Prehypertension in young physically active adults: early vascular alterations and implications for exercise-intensity...

Prehypertension represents an early stage of vascular dysfunction and an important precursor of cardiovascular disease. It remains unclear whether early vascular alterations are already present in young, physically active adults and whether these alterations are accompanied by changes in aerobic capacity or inaccuracies in commonly used exercise-intensity prescription methods.

Participants included 51 recreationally active young adults (age, 24.5 ± 2.6 years). They were categorized as normotensive (n = 26) or prehypertensive (n = 25). Central and peripheral hemodynamics were assessed using oscillometric pulse wave analysis and pulse wave velocity. Participants performed a maximal cardiopulmonary exercise test to determine maximal oxygen uptake ( $\dot{V}{O}_{2\max }$ ) and ventilatory thresholds. Fixed relative intensity anchors based on percentage of maximal heart rate, heart rate reserve, and maximal oxygen uptake were evaluated for their ability to estimate exercise-intensity domains corresponding to ventilatory thresholds.

Prehypertensive participants exhibited higher aortic pulse pressure and carotid-femoral pulse wave velocity (both p < 0.001), indicating less favourable central vascular characteristics. In contrast, aerobic $\dot{V}{O}_{2\max }$ , ventilatory thresholds, and exercise heart-rate responses were comparable between groups (all p > 0.05). Fixed relative intensity anchors showed limited accuracy in approximating exercise-intensity domains defined by ventilatory thresholds, with pronounced misclassification at the first ventilatory threshold (VT1) and better agreement at the second ventilatory threshold (VT2). Among the evaluated approaches, population-derived % $\dot{V}{O}_{2\max }$ anchors showed the lowest estimation error at VT1, whereas %HRmax anchors demonstrated the best agreement at VT2.

In young, physically active adults, prehypertension is associated with early central vascular alterations despite preserved aerobic capacity. Commonly used fixed relative intensity anchors do not accurately reflect physiological exercise-intensity domains, highlighting the need for more individualized approaches to exercise prescription in this population.