Influence of continuous photostimulation on catecholamine urinary excretion in patients with cerebral hemorrhage.

Hypertensives with (25 cases) or without (27 cases) cerebral hemorrhage (CH) and normotensives (25 cases) were exposed from 7 to 8.30 a.m. to a low light input and from 8.30 to 10 to a high light input (HLI), and urinary epinephrine (E) and norepinephrine (NE) were measured at the end of these periods. In normotensives HLI had no effect on E and NE excretion; in hypertensives with and without CH it increased E excretion and depressed NE excretion. Light activation of E release may be responsible for the daytime occurrence of CH in hypertensives.