Caffeine is a drug derived from the leaves and seeds of various plants. Some manufacturers produce artificial caffeine, which has the same effects as the naturally occurring variety. When you ingest caffeine, it stimulates your central nervous system. Effects include heightened alertness and elevated mood, which can last up to six hours. Caffeine also can cause your blood pressure to increase, though the specific effects vary among people.
Expert Insight
Experts aren't sure why caffeine causes your blood pressure to spike. It might be that caffeine inhibits a hormone that keeps your arteries widened, or caffeine might stimulate your adrenal gland to increase adrenaline production, according to Sheldon G. Sheps, M.D., of the Mayo Clinic. Whatever the reason, it doesn't take much caffeine to produce these effects. Just two to three cups of coffee can raise your blood pressure dramatically for a short period of time.
Tolerance
It's also possible to develop a tolerance for caffeine, meaning your blood pressure won't spike to the same degree that it would for other people if they ingested the same amount of caffeine. Also, you may not have negative long-term effects from caffeine. However, this doesn't mean you should drink as much caffeine as possible to develop a tolerance for it. The safest approach is to limit your overall caffeine intake to maintain a steady blood pressure.
High Blood Pressure
Generally, if you have high blood pressure, you should give up caffeine completely. This includes coffee, tea or any other beverages that contain caffeine. If having some caffeine in your diet is important to you, discuss your options with your doctor, who can offer you specific advice that takes your health condition into consideration.
Effect
You can observe the effects caffeine has on your blood circulation by taking your blood pressure after you drink a caffeinated beverage. First, take a baseline measurement before you drink the beverage so you can determine if there is a change. Then take a second measurement 30 minutes after you drink a caffeinated beverage. A difference of five to 10 points indicates you are sensitive to caffeine, meaning you might need to avoid caffeine to maintain low blood pressure. Talk to your doctor to determine your specific risk levels.
