Many people ingest caffeine on a daily basis, whether through coffee, tea or soft drinks. Energy drinks, chocolate and some medications may also be sources of caffeine. While this habit may not create any problems for most people, caffeine can have an impact on your blood pressure.
Coffee and Blood Pressure
According to Dr. Sheldon Sheps, writing for the MayoClinic.com, 2 to 3 cups of coffee can raise both blood pressure number readings by up to 14 mm for the top --- or systolic --- reading, and up to 13 mm for the bottom reading. The possible mechanisms, says Dr. Sheps, include blocking a hormone that helps keep your arteries widened or causing an increase in adrenalin, which makes your blood pressure go up. These changes don't happen to everyone, but some people who ingest caffeine on a regular basis do have a higher blood pressure than those who are caffeine free.
Caffeine and Hypertension
A research team led by Terry R. Hartley reported in the January 2000 issue of "Hypertension" that if you have a risk of hypertension, caffeine causes increasingly large blood pressure responses. They found that men who already had a diagnosis of hypertension had a pre-to-postdrug change in BP that was more than 1.5 times greater than the group with optimal blood pressure. Men with normal blood pressures did not show the caffeine effect, but men who had prehypertension did react to caffeine. In other words, a high normal blood pressure may increase enough after ingesting caffeine to put you in the hypertension range.
Hypertension Medications
In an older study reported in the 1999 issue of "Hypertension", Valentina Rakic, Valerie Burke and Lawrence J. Beilin noted that patients with hypertension had increases in ambulatory blood pressure after caffeine, even when they were on medication for hypertension. Caffeine can also interact with medications, including medications for high blood pressure. Caffeine may interact with the beta-blockers propranolol and metoprolol, both of which are used to treat high blood pressure. The interaction makes the medications less effective and results in a higher overall blood pressure.
Considerations and Warnings
If you think caffeine might be affecting your blood pressure, take a blood pressure reading within 30 minutes of ingesting your normal source of caffeine. A rise of 5 to 10 points could mean you are caffeine sensitive. Do not make changes in your medication as a result of this home test. If you are already on medication or have concerns or questions, be sure to talk to a health care professional about whether caffeine is a potential problem for you.
References
- MayoClinic.com; How Does Caffeine Affect Blood Pressure?; Sheldon G. Sheps, M.D.; November 2009
- "Hypertension"; Hypertension Risk Status and Effect of Caffeine on Blood Pressure; Terry R. Hartley, Bong Hee Sung, Gwendolyn A. Pincomb, Thomas L. Whitsett, Michael F. Wilson, William R. Lovall; January 2000
- "Hypertension"; Effects of Coffee on Ambulatory Blood Pressure in Older Men and Women: A Randomized Controlled Trial; Valentina Rakic; Valerie Burke; Lawrence J. Beili; 1999
- University of Maryland Medical Center: Possible Interactions With: Green Tea
