Confusion surrounding caffeine’s effect on blood pressure is long-standing. It was originally thought to lower blood pressure but subsequently believed to raise it. In 1988 Myers reviewed seventeen intervention trials and cross-sectional studies (1). He concluded that “…caffeine does not produce a persistent increase in blood pressure. Individuals who do not regularly consume caffeine may experience a slight increase in blood pressure when they are exposed to caffeine, but tolerance develops rapidly and blood pressure returns to baseline”.
The results of studies on subjects with normal blood pressure published since this review confirm its conclusions. An intervention trial in moderate coffee drinkers showed that moderate daily consumption of coffee does not elevate blood pressure measured in an outpatient clinic (2). A second intervention trial in habitual coffee drinkers showed that caffeine supplements produced a small increase in ambulatory blood pressure which returned to normal after three days (3). A third intervention trial in habitual coffee drinkers showed that abstaining from caffeine for 9 weeks had no effect on blood pressure (4).
Codrington (capital of Barbuda),
City of Lithgow, Australia,
Mongolia, Ulan Bator,
St. Vincent and The Grenadines, Kingstown