Caffeine and high blood pressure are often considered linked because of the stimulant effect of caffeine. Extensive medical research has been done on the question of whether caffeine and high blood pressure may be linked, with most studies returning fairly similar results. Although caffeine has been shown to make blood pressure spike, this condition is usually considered temporary and is not considered a risk for permanently raising blood pressure.
Caffeinated beverages are undoubtedly the most popular type of drink in the world, and are a common factor in nearly every culture. Coffee, tea, and cocoa are among the most popular varieties of caffeinated drink, for a variety of reasons that include taste, availability, and the naturally stimulating effect of caffeine. As a stimulant, caffeine causes a temporary increase of central nervous system activity. The result is usually a feeling of alertness or increased energy, though this may turn to jitters and anxiety after excess consumption.
The link between caffeine and high blood pressure lies in the fact that caffeine has a mild vasoconstricting effect, meaning that it narrows blood vessels. Narrow vessels require the heart to pump blood harder or faster to force the same volume of blood through a smaller than normal passageway. Shortly after caffeine enters the body, studies show that blood pressure may rise significantly for a brief period of time. This short jump may be the connection between caffeine and high blood pressure.
On a long-term scale, however, very little evidence supports a link between caffeine and high blood pressure that develops into hypertension, a chronic form of high blood pressure. In some studies, some people with hypertension actually showed a blood pressure decrease after drinking caffeinated beverages. Most medical experts agree that heart disease, heart attack, and hypertension risks are not associated with intake of caffeine in any way. Some experts even argue that the antioxidants and polyphenols present in some caffeinated drinks, such as green tea, may be extremely beneficial to people.
Since many people consume caffeine on a regular or daily basis, some medical experts theorize that the body builds up a tolerance to the vasoconstricting effects of the stimulant. Some evidence suggests that people who drink no caffeine and those who drink large amounts have virtually the same level of risk for developing hypertension. In cases where hypertension already exists, doctors tend to still warn against caffeine, since any additional temporary pressure on the already-narrowed vessels may be somewhat detrimental. Few studies, however, suggest that caffeine can make hypertension worse in the long run.