A fragrant, steaming cup of tea can brace you against winter's chill, and on ice, tea cuts the heat with no added fat or sugars. Black teas have a pleasantly astringent taste and floral aroma, and green teas have a fresh, grassy flavor. Tea makes a healthful alternative to sugary sodas, but certain types also contain caffeine that might trouble you if you have existing high blood pressure or heart disease.
Blood Pressure
Your heart works to pump blood out to your body, and your blood vessels serve as the delivery system. Blood pressure readings reflect the pressure of blood against your vessel walls. Your heartbeat increases in reaction to stimuli, including emotional triggers such as anger or fear, hormones released into your bloodstream, and chemicals ingested, such as caffeine. When your heart beats faster, your blood volume increases. Increased blood volume can result in increased blood pressure. Although your blood pressure continually fluctuates, and although your body counteracts changes to keep the swings in check, too much of any stimulus or drug can cause problems.
Caffeine Basics
Caffeine is drug naturally found in plants such as camellia leaves and in cocoa and coffee beans. It stimulates your nervous system, increasing mental alertness and your heart rate. Caffeine also interacts with other chemicals in your body, resulting in vasoconstriction, or constricted blood vessels. The combination of increased heart rate, constricted blood vessels and increased blood volume results in a temporary rise in your blood pressure when you ingest caffeine. Health professionals consider a moderate amount of caffeine to be 200 mg per day, the equivalent of two cups of tea. Tea contains less caffeine than coffee, and some types don't contain caffeine at all.
Tea Types
Black tea and green tea both come from leaves of Camellia sinesis. The preparation of the leaves determines what label the teas obtain and how much caffeine ends up in your cup. All brews made from Camellia senesis contain some caffeine, but true herbal teas brewed from flowers, fleshy rhizomes and leafy plants do not contain caffeine. Examples include tea made from chamomile, ginger and mint. Check the label on the package to make sure what goes into your teapot. Pregnant women specially need to check with health care providers about which options are safe. Some flavored black teas taste similar to herbal teas, but contain caffeine and can raise blood pressure.
Considerations
Caffeinated tea can help elderly people deal with orthostatic and postprandial hypotension, conditions in which a sudden drop in blood pressure occurs after positional changes or meal consumption. Sudden drops in blood pressure can cause dizziness and falls, so a cup of coffee or tea taken with a meal can help prevent unpleasant and potentially dangerous side effects. Consult with a doctor before starting or stopping caffeine consumption if you have any health conditions or concerns.
