The Effects of Coffee on High Blood Pressure

The effect of coffee on blood pressure has been the subject of much research and considerable controversy. Experts in the field are not in agreement and scientific studies frequently contradict one another about whether coffee actually raises blood pressure, but one thing is agreed upon.: If you suffer from hypertension, the goal is to lower your blood pressure, and consuming caffeine is contradictory to that end.

Hypertension Defined

• Hypertension refers to the amount of blood pumped by your heart and the resistance if faces traveling through your arteries. An estimate 50 million people in the United States have hypertension, increasing their risk for coronary heart disease, stroke and congestive heart failure. Hypertension takes many years to materialize, sometimes not showing any symptoms at all. It is easily detected and can be treated with lifestyle changes.

Coffee & Caffeine

• The amount of caffeine in coffee varies by brand and producer. On average, a cup of espresso contains the most caffeine, about 185 mg per shot. Drip coffee is next, with 115-175 mg per cup, and then pressed with 80-135 mg per cup. Instant coffee contains approximately 65-100 mg per cup and decaffeinated coffee contains 3-4 mg per cup, slightly less for instant decaffeinated.

Side Effects of Caffeine

• Common side effects of caffeine include tachycardia or rapid heart rate, heart palpitations, insomnia, restlessness, nervousness, tremor, headache, abdominal pain, nausea, vomiting, diarrhea and diuresis. These effects occur at different amounts of consumption, depending on individual physiology; some people are simply more sensitive to caffeine then others. Consumption of caffeine has the potential to raise your systolic blood pressure by 3 to 13 mm Hg and your diastolic blood pressure by 4 to 13 mm Hg. People unaccustomed to consuming caffeine experience a temporary, but stark, increase in blood pressure. To see if coffee raises your blood pressure, have your blood pressure taken prior to, and again 30 minutes after, consuming coffee.

Conflicting Research

• A long-term study of white males supported by the National Institute on Aging and conducted by Johns Hopkins researchers concluded that coffee intake increased the risk of developing hypertension, but also concluded that coffee drinkers were more likely to drink alcohol and smoke cigarettes, making it unclear if the coffee was the causal link in the development of the condition. Harvard researchers published the results of a long-term study of women in the Journal of the American Medical Association in 2005, indicating that coffee consumption might protect them against developing hypertension, but consuming caffeine in the form of cola increased the risk of hypertension. Women who drink in excess of six cups of coffee per day had a low risk for hypertension, but those who drank less then three had a high risk. Consideration must be given to other risk factors in the lifestyles of people who develop hypertension.

Coffee vs. Cola

• It is unclear what component of cola affects blood pressure; sugared or diet cola both produce similar results. According to a Harvard University study, women who drink more then one soda per day are 44 percent more likely to develop hypertension then women who consume large amounts of coffee or less then one soda daily. The greatest risk is for women aged 43-71. Research is not conclusive for men.