Caffeine may potentiate adrenocortical stress responses in hypertension-prone men.

Abstract

The effect of caffeine on blood cortisol levels and blood pressures was examined during rest and in response to a challenging psychomotor task in men with a low versus high risk of essential hypertension. Thirty-four healthy men ages 21-35 years were selected such that 17 were at high risk for hypertension (positive parental history and screening blood pressures of 135/85-155/95 mm Hg) and 17 were at low risk (negative parental history and no pressures above 132/84 mm Hg). Testing consisted of quiet rest (20 minutes); oral placebo (grapefruit juice) or caffeine administration (33 mg/kg in grapefruit juice); rest during a postdrug absorption period (40 minutes); work on an unsignalled simple reaction time task (15 minutes); and quiet rest (20 minutes). Blood pressures were recorded at 2-minute intervals, and blood samples were withdrawn via an indwelling catheter at the end of the baseline, drug absorption, task, and recovery periods. The combination of task plus caffeine produced the highest blood pressures in men at risk for hypertension. Cortisol levels were found to be sustained during rest in members of the high risk group after they had consumed caffeine, whereas members of the low risk group showed a modest decline. The high risk subjects also showed a significant rise in cortisol during (+3.7 Aig/dl) and after (+4.0 Atg/dl) work on the reaction time task after caffeine consumption. In the low risk group, cortisol responses to caffeine were smaller (+2.2 /tg/dl or less) when compared with responses to the task after caffeine consumption. The results suggest that these men at high risk for hypertension were sensitive to caffeine and that caffeine combined with a demanding psychomotor challenge produced neuroendocrine signs of stress. These findings point toward the need for studies of the role of caffeine in modifying stress responses of targeted groups such as those at risk for hypertension. (Hypertension 1989;14:170-176) T he present study examined the effects of caffeine on plasma cortisol concentrations and blood pressures during periods of rest and work on a demanding psychomotor task in men considered to be either low or high in risk for essential hypertension. Caffeine is a widely used substance that has effects on central nervous system, cardiovascular, and neuroendocrine functions. The best documented cardiovascular effect of caffeine is its ability to increase blood pressure at

Caffeine Stimulation of Cortisol Secretion Across the Waking Hours in Relation to Caffeine Intake Levels

“…Other evidence, in light of the present results, indicates that the pattern of cortisol tolerance formation may vary as a function of hypertension risk (35,36). Hypertension is accompanied by enhanced responsivity of the HPAC (36,37), consistent with reports of greater numbers of hypothalamic corticotropin-releasing factor neurons in spontaneously hypertensive rats and in brain tissue taken from deceased hypertensive patients (38).…”

Cortisol responses to mental stress, exercise, and meals following caffeine intake in men and women

“…Caffeine increases cortisol levels during periods of stress (Lovallo et al, 1989(Lovallo et al, , 1996Lane et al, 1990;Sung et al, 1990) both in the lab and in daily life (Lane, 1994), during naturalistic stressors such as medical school examinations (Shepard et al, 2000), and in relation to exercise (Laurent et al, 2000;Sung et al, 1990). Caffeine's effect on cortisol may be greater in persons with higher levels of central nervous system activation, such as those at high risk for hypertension (al'Absi et al, 1998).…”

Coffee, caffeine and blood pressure: a critical review

“…The pressor response to caffeine seems to be more pronounced in hypertensive or hypertension-prone subjects than in normotensive subjects (Smits et al, 1986a;Greenstadt et al, 1988;Sung et al, 1994;Lovallo et al, 1996b). The effect has been shown to be additive or enhanced during mental and physical stress (Greenstadt et al, 1988;Pincomb et al, 1988Pincomb et al, , 1991Lovallo et al, 1989Lovallo et al, , 1991Lovallo et al, , 1996bMyers et al, 1989;Lane et al, 1990;France & Ditto, 1992).…”

“…In normotensive and hypertensive subjects, caffeine caused stress-like increases in plasma adrenocorticotropin (ACTH) and cortisol concentrations (Lovallo et al, 1996a) and potentiated stress-related increases in plasma cortisol (Pincomb et al, 1988;Lovallo et al, 1989;Lane et al, 1990). Corticosteroids can in¯uence vascular tone, e.g.…”