Haemodynamic effects of coffee and caffeine in normal volunteers: a placebo-controlled clinical study.

The acute haemodynamic effects of Italian coffee and 200 mg purified caffeine were investigated in 15 healthy non-coffee-drinkers compared to individuals who consumed placebo (highly decaffeinated coffee for regular coffee, and china bitter extract for caffeine). Before coffee and caffeine consumption and 30, 60, 90 and 120 min afterwards, rest flow and blood pressure were measured, and peripheral resistance in the arm was calculated; an echocardiogram was also performed before and 60 and 120 min after caffeine consumption. Both coffee and caffeine significantly decreased rest flow, and increased peripheral resistance. Systolic blood pressure increased by 10% and diastolic pressure increased by 5% for at least 2 h. No variation in heart rate or cardiac contractility was found. No effects were observed after placebo treatment. It is concluded that Italian coffee and caffeine increase blood pressure via vasoconstriction (PART 2).