Plasma epinephrine concentration in healthy men: correlation with systolic pressure and rate-pressure product.

Relations among plasma epinephrine, norepinephrine and renin activity and systolic pressure, diastolic pressure, heart rate and the product of heart rate and systolic pressure (rate-pressure product) were evaluated in 31 healthy men whose arterial pressure spanned the range from normal to mildly elevated. Measurements were made during 60 minutes with the patient in the supine position and during 10 minutes of quiet standing. In the supine position, highly significant regressions were found between systolic pressure or rate-pressure product and plasma epinephrine, but not between these variables and norepinephrine or renin activity. A weakly significant correlation was also found between heart rate and norepinephrine. On standing, norepinephrine and epinephrine increased significantly. In this position, rate-pressure product was significantly related by regression analysis only with plasma epinephrine. Weakly significant correlations between systolic pressure and epinephrine and between heart rate and norepinephrine and epinephrine were also found. Plasma renin activity was not significantly correlated with arterial pressure, heart rate or rate-pressure product in either position. These results suggest that plasma epinephrine is a determinant of systolic pressure when postural reflexes are minimized and that epinephrine may participate in control of cardiac work load, as reflected by rate-pressure product in the absence of exercise or definable stress.