Defining the effect of coffee on blood pressure

Some say drinking coffee is associated with slightly higher blood pressure. However, these studies followed patients for less than 85 days.

Researchers around the US collaborated to review the results of longer term studies.

First, the details.

• From 6 studies, a total of 172,567 participants (37,135 with hypertension) were included in the review.

And, the results.

• The average duration of follow-up ranged from 6 to 33 years.
• A meta-analysis of the combined data showed that habitual coffee consumption of greater than 3 cups/day was not associated with an increased risk of hypertension compared with less than 1 cup/day.
• A slightly elevated risk appeared to be associated with light-to-moderate consumption of 1 to 3 cups/day.”

The bottom line?

So, the risk is low. But how much of a rise in blood pressure can we expect and why does it happen?

Dr. Sheldon Sheps, a specialist in hypertension at the Mayo Clinic tells us, “The amount of caffeine in 2 to 3 cups of coffee can raise systolic pressure (the top number in your blood pressure reading) 3 to 14 millimeters of mercury (mmHg). Your diastolic pressure (the bottom number) can be increased 4 to 13 mmHg.”

“It’s unclear what causes this spike in blood pressure. Caffeine could block a hormone that helps keep your arteries widened. Others think that caffeine causes your adrenal gland to release more adrenaline, which causes your blood pressure to increase.”

5/21/11 21:28 JR