Sunday, September 25, 2011

Coffee, Caffeine and Blood Pressure

Does coffee or caffeine increase blood pressure? Patients often wonder if their blood pressure measured in the office is higher because of the coffee they drank just before the visit. Could that be true? Should you cut down on coffee or caffeine if your blood pressure is up?

A detailed review of the effect of caffeine on blood pressure was just published. Although coffee contains many chemical substances, caffeine is the component with the main effect on blood pressure. So decaf coffee was not addressed in this paper.

Most of the studies in this publication used 200-300 milligrams of caffeine in their tests. This amount of caffeine is roughly equivalent to 1 and ½ to 2 cups of coffee.

So what did this review of coffee, caffeine and blood pressure show?

If you are not regularly drinking coffee every day, then blood pressure can definitely increase starting at 1 hour after drinking and lasting 3 hours or more.
And the increase in blood pressure is not trivial.

8 mm in the systolic (upper number) and 6 in the diastolic (lower number) have been seen on average. So this is a significant increase in blood pressure that happens when caffeine is given to those who were not using caffeine for 1-2 days or more. And the increase in blood pressure with caffeine was seen in both those taking and not taking medication for high blood pressure.

But what happens if you drink coffee every day? Does regular caffeine or regular coffee drinking increase blood pressure and turn someone who has normal blood pressure into someone with high blood pressure?

The best evidence indicates that it probably does not. Maybe the other chemical components of coffee help or maybe you just adapt to the effects of the caffeine.

And other questions still remain.
For example is heavy consumption of coffee harmful in those with uncontrolled high blood pressure?

The good news is that there is no evidence that long term regular coffee use increases the risk of cardiovascular disease such as heart attacks.

More studies are needed but it appears that if you enjoy your coffee, you should do so every day. And if you drink it every day, the coffee is not likely causing increased blood pressure.

And keep in mind, you can always consider lowering your caffeine intake.
How about green tea or decaf coffee?

And when blood pressure control is in doubt, testing your blood pressure at home or, even better, 24 hour ambulatory blood pressure monitoring can be very informative. 
More about blood pressure monitoring in an upcoming post.

Your Diabetes Endocrine Nutrition Group 

1 comment:

  1. cool artical im doing a project on caffeine and how it affects your blood pressure and this really helped thank you oh so much <3