Greater Daily Psychosocial Stress Exposure is Associated With Increased Norepinephrine-Induced Vasoconstriction in Young Adults

Background Epidemiological data suggest a link between psychological stress and increased cardiovascular disease risk; however, the underlying mechanisms remain incompletely understood. The purpose of this investigation was to directly examine the influence of daily psychosocial stress on microvascular adrenergic vasoconstrictor responsiveness in healthy adults. We hypothesized increased daily psychosocial stress would be positively related to increased norepinephrine-induced vasoconstriction. Methods and Results Eighteen healthy adults (19-36 years; 10 women) completed a daily psychosocial experiences telephone interview for 8 consecutive evenings in order to document their exposure and emotional responsiveness to common stressors (eg, arguments, work stress) over the preceding 24 hrs. On the last interview day, red cell flux (laser Doppler flowmetry) was measured during graded intradermal microdialysis perfusion of norepinephrine (10(-12) to 10(-2) mol/L) and expressed as a percentage of baseline vascular conductance. Exogenous norepinephrine elicited progressive and robust vasoconstriction in all individuals (maximal vasoconstriction: 71 +/- 4%(base); cumulative vasoconstriction [area under the curve]: 118 +/- 102 arbitrary units). Participants experienced a stressor on 51 +/- 5% of days and a total of 5.2 +/- 0.9 stressors over the 8-day time frame. Increased daily frequency of stressor exposure was positively related to both maximal (R-2=0.26; P=0.03) and cumulative (R-2=0.31; P=0.02) vasoconstrictor responsiveness. Likewise, the total number of stressors was associated with increased maximal (R-2=0.40; P<0.01) and cumulative (R-2=0.27; P=0.03) norepinephrine-induced vasoconstriction. Neither stressor severity nor stress-related emotions were related to vasoconstrictor responsiveness. Conclusions Collectively, these data suggest that daily psychosocial stressor exposure by itself is sufficient to adversely influence microvascular vasoconstrictor function, regardless of the perceived severity or emotional consequences of the stressor exposure.