Haemodynamic effects of coffee and purified caffeine in normal volunteers: a placebo-controlled clinical study
Casiglia, E.; Paleari, C.D.; Petucco, S.; Bongiovì, S.; Colangeli, G.; Baccilieri, M.S.; Pavan, L.; Pernice, M.; Pessina, A.C.
Journal of Human Hypertension 6(2): 95-99
1992
ISSN/ISBN: 0950-9240 PMID: 1597852 Document Number: 390997
To evaluate the effects of 'espresso' Italian coffee on resting flow, blood pressure (BP) and peripheral resistance, 15 non-coffee drinking healthy volunteers received 2 cups of regular coffee, purified caffeine 200 mg or placebo in a latin square double-blind crossover protocol. Before and 30, 60, 90 and 120 min after ingestion, segmental resting flow and BP were measured and peripheral resistance was calculated. An echocardiogram was also performed before and 60 and 120 min after caffeine intake. Both regular coffee and caffeine produced a significant decrease in resting flow and a significant increase in resistance; both systolic and diastolic BP also increased, although not significantly. No variation was observed in heart rate and in cardiac contractility. Placebo (highly decaffeinated coffee for regular coffee and china bitter extract for caffeine) did not produce any haemodynamic effect. In 5 other healthy volunteers who drank more than 5 cups of coffee daily, coffee administration had no effect. It is concluded that the caffeine contained in espresso Italian coffee is a vasoconstrictor agent whose effects are reduced in habitual coffee drinkers due to adaptation.