Low renin-aldosterone in "prehypertensive" young adults.

PRA is suppressed in approximately 25% of patients with essential hypertension. To determine if renin suppression precedes the onset of hypertension, PRA and plasma aldosterone were measured before and after treadmill exercise in 129 young adults with relatively high, intermediate, or relatively low blood pressures sustained over 5 yr. PRA and aldosterone responses to exercise were lower (P less than 0.01) in the high blood pressure group. In contrast, plasma renin substrate was lower (P less than 0.01) in the low blood pressure group. Unrelated to blood pressure, PRA, but not aldosterone, was lower in black than in white subjects both before and after exercise. In conclusion, renin suppression precedes the onset of hypertension and may be an appropriate response to higher levels of arterial pressure.