Caffeine can cause blood pressure to increase dramatically for a brief time. Drinking two or three cups of regular coffee can raise a person's systolic blood pressure as well as diastolic pressure by 3-14 millimeters of mercury (mmHg). This is temporary, however, and blood pressure returns to normal after two or three hours. Over the long term, there is no evidence to suggest that there is a connection between coffee and high blood pressure.
Drinking caffeinated coffee is not associated with a substantial increase in risk for those suffering from high blood pressure or hypertension. For long-term coffee drinkers, there is little effect on blood pressure, but if that difference is important, then a switch to decaffeinated coffee is advised. Caffeine is also present in other drinks, such as some energy drinks and soft drinks.
If blood pressure has risen by five to 10 points within half an hour of drinking coffee, then sensitivity to the blood pressure-raising effects of caffeine can be assumed. In this case, caffeine reduction is logical. Consuming no more than two average cups of brewed coffee a day, which is equal to 200 milligrams of caffeine, should limit the connection between coffee and high blood pressure. Caffeine also should be avoided before beginning any activity that increases blood pressure, such as exercise, for those who are sensitive to caffeine.
Exactly why there is a connection between coffee and high blood pressure, however slight and short-lived, is still unknown. One theory is that caffeine blocks a hormone that ensures that arteries stay wide, resulting in blood vessel constriction. Another theory is that caffeine causes the release of adrenaline, which causes the heart to beat faster and raises blood pressure.
Other factors, such as smoking, lack of exercise and overeating, are more likely to increase blood pressure. These behaviors are more likely to be indulged in by ardent coffee drinkers than those who do not indulge too much. It likely is not the coffee that is to blame, though, it is the cigarette, biscuits or other item that accompanies the coffee that leads to high blood pressure.
Caffeine tolerance reduces the short-term connection between coffee and high blood pressure. More of an effect on blood pressure has been found in those who drink from one to three cups of coffee a day, compared to those who drink six or more. Although there is no substantial connection between coffee and high blood pressure, however, a lot of caffeine can have detrimental effects on cholesterol levels.