Does caffeine raise blood pressure?

Dear Alice,

Does caffeine raise your blood pressure?

Dear Reader,

You raise a good question! While the exact mechanism is unknown, it seems that caffeine can cause a temporary increase in blood pressure among those who don’t have high blood pressure (HBP). Some researchers have hypothesized that caffeine either blocks a hormone that helps keep the arteries widened, forcing the same amount of blood to flow through more narrow veins, or it causes your adrenal glands to release more adrenaline, which results in increased blood pressure. Each person may have a different tolerance for caffeine, so those who consume caffeine regularly may not see as big of an impact on their blood pressure. That being said, it’s also been noted that caffeine has a stronger effect on the blood pressure of men who are overweight or older than 70 years old. All that said, there are also some studies that have shown that when there’s a higher concentration of caffeine metabolites in someone’s system, the less likely they are to have HBP. Though there’s limited evidence to suggest that caffeine can cause high blood pressure, it’s recommended that those who’ve already been diagnosed with HBP (also called hypertension) consider consuming less caffeine.

In order to understand changes in blood pressure, you may find it helpful to know about how blood pressure is measured: it’s considered the measure of force exerted against the arteries. The systolic blood pressure is the measure when the heart beats, while the diastolic blood pressure is the measure between heart beats. The two numbers together create a blood pressure reading. This is measured in millimeters of mercury (notated as mm Hg). For reference, classification of blood pressure is as follows:

  • Normal blood pressure: Systolic is less than 120 and diastolic is less than 80
  • Elevated blood pressure: Systolic is 120 to 129 and diastolic is less than 80
  • Stage 1 HBP: Systolic is 130 to 139 or diastolic is 80 to 89
  • Stage 2 HBP: Systolic is more than 140 or diastolic is more than 90

List adapted from the American Heart Association.

Generally speaking, it may be a good idea to refrain from ingesting caffeine just before a blood pressure test to avoid an inaccurate reading. Though coffee may be the most common culprit, chocolate, soda, and energy drinks have varying amounts of caffeine as well. If you’re wondering whether caffeine affects your blood pressure, you could try measuring your blood pressure before your next cup of coffee (or caffeinated food or beverage) and again within 30 to 120 minutes. If your reading goes up by five to ten points in that period of time, it may indicate sensitivity to the effects of caffeine.

If you’re considering cutting out caffeine, it’s recommended to do so gradually to avoid experiencing withdrawal symptoms. Can’t give up good ol' java? Decaffeinated coffee may serve as a suitable substitute, with a typical caffeine content of about 5 milligrams (mg) per 8 ounce (oz.) cup (versus around 135 mg of caffeine for the regular brew). Hot cocoa is another option that contains approximately 5 mg of caffeine per 8 oz. (with an added bonus of calcium and er… chocolate!). There are also herbal teas, which contain no caffeine and are available in a variety of flavors. Your local grocery store or health foods store may also have a few additional offerings, including non-caffeinated herbal teas.

Hope this information helps to balance your caffeine intake and your blood pressure!

Last updated Jan 01, 2021
Originally published Sep 06, 2001

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