Millions of Americans suffer from high blood pressure and heart disease, and many are told that restricting caffeine intake is important in maintaining lower blood pressures. Unfortunately, caffeine is a popular ingredient in many common products that are frequently used by a large portion of the population.
Sources of Caffeine
In order to succeed in their jobs, most workers need to be focused, alert and energetic. Many people start the day with a caffeinated beverage such as coffee, lattes or espressos. Caffeine has been shown to have a stimulating effect on the brain and improve alertness. Caffeine also is a major component in popular beverages, including soda and energy drinks. In addition, caffeine might be found in headache medications, and some people even use caffeine tablets to boost energy and alertness.
Blood Pressure
A simple calculation of blood pressure can be seen in this equation: Blood pressure equals cardiac output times peripheral resistance, or BP= CO x PR. From this equation, it can be seen that any factors that contribute to increased peripheral resistance in arterial blood vessels also will have an increasing effect on blood pressure. Caffeine is believed to cause elevations in blood pressure through increased peripheral resistance.
Caffeine and Blood Pressure
According to a study titled "Hypertension Risk Status and Effect of Caffeine on Blood Pressure" published in the journal "Hypertension" in 2000, Terry Hartley and colleagues examined the effects of caffeine on blood pressure. The study reported that caffeine intake did acutely increase blood pressure. In addition, the study found that the most significant increase occurred in groups that started with higher baseline systolic blood pressures.
How Caffeine Increases Blood Pressure
Although the pressor effects of caffeine are well-documented, the exact mechanism causing increased blood pressure remains undetermined. Some researchers believe caffeine blocks receptors targeted by adenosine, which under normal circumstances might have a vasodilation effect on blood vessels. As blood vessels remain in a more constricted state, peripheral resistance and blood pressure increase. Other researchers have speculated that caffeine might directly stimulate constriction mechanisms. In addition, as caffeine stimulates alertness, increased mental and physical activity can cause an increase in heart rate, which also can increase blood pressures.
Significance
High blood pressure is a major risk factor for the development of cardiovascular diseases, including heart failure, stroke and heart attacks. In order to avoid higher blood pressure, it might be important to restrict caffeine intake. Evidence suggests that this is especially true in patients who have been diagnosed as hypertensive. Patients should discuss the best treatment and lifestyle modifications for hypertension with their physician.
