Cardiovascular effects of caffeine in elderly men.

Ten healthy elderly male volunteers were given 4 mg/kg of caffeine by intravenous infusion on three separate occasions. This resulted in mean peak plasma concentrations of caffeine of 7.4 +/- 0.7 micrograms/ml. Immediately after each of the three caffeine infusions, the mean systolic blood pressures increased 14, 7, and 16 mm Hg, and the mean diastolic blood pressures increased 7, 4, and 7 mm Hg, respectively. Both the systolic and the diastolic blood pressures returned to preinfusion values within 4 hours. The QS2 index and the left ventricular ejection time (LVET) index increased after caffeine, probably as a result of the caffeine-induced increase in arterial blood pressure. The pre-ejection period (PEP), the PEP/LVET ratio, and the diastolic time remained unchanged. Caffeine, in doses equal to those contained in 2 to 3 cups of coffee, produces an increase in blood pressure but has no demonstrable positive inotropic effect in healthy elderly men.