THE EFFECT OF COFFEE ON BP
As a coffee aficionado, I have been following the reports which concluded that avid coffee drinkers develop less type 2 diabetes and experience no increases in BP, despite earlier evidence to the contrary. Now, a new study claims that while peripheral BP is not significantly elevated in chronic coffee drinkers, central BP is. What is central hypertension? And of what significance is it?
—Robert M. Foster Jr, MD, Roxboro, N.C.
Coffee can increase heart rate and BP for a few hours. In most studies, this effect is small, but it can vary from individual to individual, with a larger effect in some. Coffee together with cigarettes raises BP more, and effects can last for hours.
The term “central hypertension” refers to central aortic BP, which may differ from peripheral (e.g., brachial) BP. Central aortic BP always has a lower pulse pressure than peripheral pressure. In some instances, the central pressure is higher or lower than the peripheral BP, as determined by analysis of the peripheral pulse wave. The accuracy of estimating the central pressure in the individual patient is not as reliable as its proponents would claim. Does the effect of coffee on central BP differ from its effect on peripheral pressure, or does this effect differ from that of any other stimulant? I don’t know, and I doubt whether the answer is truly known. At present, it would be premature to reach clinical conclusions based on central aortic pressure data. The inverse relationship between coffee and the development of diabetes is an interesting finding but requires a lot more evidence before it is to be believed.
—Samuel J. Mann, MD (114-17)