High blood pressure can result in cardiovascular damage, stroke and premature death. If you suffer from hypertension -- diagnosed by readings greater than 140 over 90 -- finding ways to control your blood pressure without completely relying on medication can be challenging. While dietary changes such as limiting sodium are know to play a role in the management of hypertension, the benefits of limiting other substances like caffeine is less certain.
Caffeine
In 2000, researchers at the Oklahoma City Veterans Affairs Medical Center investigated how caffeine ingestion might affect blood pressure. The researchers divided 182 men into groups based on their hypertension risk, with categories ranging from normal blood pressure to high blood pressure. Each participant's resting blood pressure was tested prior to the administration of a dose of 260 mg of caffeine. In each group, the caffeine dose temporarily raised participants' blood pressure. Blood pressure readings from men with preexisting hypertension responded most markedly, increasing 1.5 times more than in men without hypertension.
Prehypertension
One surprising finding from the 2000 Oklahoma study was the fact that 19 percent of men classified as having "high normal" blood pressure crossed the threshold into hypertensive range after a caffeine dose. This finding poses a concern for Americans who consider their blood pressure to be on the high side of normal. If your systolic blood pressure is between 120 and 139 or your diastolic falls between 80 and 89, dubbed the "prehypertensive" range, it's plausible you could cross the line into true hypertension after drinking caffeine containing beverages like coffee.
Habitual Caffeine Intake
In contradiction to the immediate blood pressure increase caused by caffeine, a 2005 study at Harvard Medical School did not establish a link between lon- term habitual caffeine consumption and hypertension. This study, published in "The Journal of the American Medical Association," monitored subjects' caffeine consumption and blood pressure status over 12 years to determine if regular caffeine consumption was association with hypertension. Subjects who developed hypertension were not more likely to be habitual caffeine drinkers. In an interesting twist, however, the study reported a significant link between the consumption of cola drinks and the development of hypertension.
Combined Effects
A study in the journal "Health Psychology" established a link between the combined effects of stress, caffeine and blood pressure in 1991. In this study, subjects were given a dose of caffeine equivalent to two and a half cups of coffee. Once the caffeine had time to enter their bloodstream, subjects worked on a demanding task requiring physical and mental exertion for 15 minutes. Throughout the evaluation, researchers monitored blood pressure. While caffeine increased blood pressure among all participants, blood pressure increased significantly during the psycho-motor exertion phase of the experiment.
References
- "Hypertension"; Multiple Biomarkers and the Risk of Incident Hypertension;Thomas J. Wang, et. al.; 2007
- "Hypertension;" Hypertension Risk Status and Effect of Caffeine on Blood Pressure; T. R. Hartley, et al., 2000
- "Journal of the American Medical Association"; Vital Signs: Prevalence, Treatment, and Control of Hypertension---United States, 1999-2002 and 2005-2008
- "Journal of the American Medical Association"; Habitual Caffeine Intake and the Risk of Hypertension in Women; W.C. Winkelmayer, et al., 2005
- "Health Psychology," Hypertension Risk and Caffeine's Effect on Cardiovascular Activity During Mental Stress in Young Men; W.R. Lovallo, et al., 1991
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