Prehypertension alters arterial pressure and forearm vascular responses to mental stress in humans

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Neurovascular responses to mental stress (MS) have been linked to several cardiovascular diseases, including hypertension. Mean arterial pressure (MAP), muscle sympathetic nerve activity (MSNA) and forearm vascular responses to MS are well documented in normotensive (NT) subjects, but responses in prehypertensive (PHT) subjects remain unclear. We tested the hypothesis that PHT would augment MS‐induced increases in MAP through altered MSNA and forearm vascular responses. We examined 11 PHT (systolic 120–139 or diastolic 80–89 mmHg; 21±1 yrs) and 11 NT (systolic <120 and diastolic <80 mmHg; 22±2 yrs) subjects during 5 min of mental arithmetic. MSNA, MAP, heart rate (HR), forearm vascular conductance (FVC) and resistance (FVR) were measured. Resting MSNA (8 ± 2 vs. 14 ± 5 bursts/min; P<0.01) and MAP (80 ± 1 vs. 90 ± 1 mmHg; P<0.001) were significantly higher in PHT subjects. PHT augmented MS‐induced increases in MAP (Δ10 ± 2 vs. Δ14 ± 4 mmHg; P<0.05) and blunted MS‐induced decreases in FVR (Δ−16 ± 2 vs. Δ−8 ± 1 units; P<0.01). PHT tended to blunt MS‐induced increases in FVC (Δ3 ± 1 vs. Δ2 ± 0 units; P=0.10). MS elicited similar increases in MSNA (Δ8 ± 2 vs. Δ8 ± 3 bursts/min) and HR (Δ23 ± 4 vs. Δ20 ± 4 beats/min) in NT and PHT subjects, respectively. We conclude that MS elicits an augmented pressor response in PHT subjects. This augmentation appears to be associated with altered forearm vascular, but not MSNA, responses. Supported by NIH.