Antioxidant-rich tea may lower your risk for cancer, stroke, heart disease and osteoporosis, according to an article published in "Antioxidants & Redox Signaling" in July 2004. But if you're worried about tea's effect on your heart rate, don't panic -- moderate consumption of tea may not be a problem. However, if you're sensitive to caffeine, decaffeinated teas may be a better choice.
Caffeine in Tea
Tea contains caffeine, with between 14 and 60 milligrams per 8-ounce cup. Drinking excessive amounts of caffeine can cause a fast heart rate. Because of this, you shouldn't drink more than five cups of tea per day, recommends MedlinePlus. If you drink more tea than this, go for decaffeinated or herbal teas instead of regular tea to limit your caffeine intake.
Tea vs. Water
Drinking three cups of black tea each day may not cause a noticeable effect on your heart rate compared to drinking the same amount of water, according to a six-month study published in "American Heart Journal" in October 2007. In fact, three months into the study, the people drinking water had higher heart rates than those drinking tea, although they had comparable heart rates at the end of the six-month study.
Tea and Exercise Combined
Men had lower heart rates during a 60-minute bout of cycling when given green tea extract than when given a placebo in a study published in the "International Journal of Sport Nutrition and Exercise Metabolism" in June 2014. This doesn't appear to occur during resistance exercise. A study published in "High Blood Pressure & Cardiovascular Prevention" in September 2014 didn't find any effect of taking green tea extract for three weeks on the heart rates of women participating in 60 minutes of resistance training. However, these studies were conducted using tea extract, so it's unknown whether the same results would occur with brewed tea.
Other Potential Considerations
An increased heart rate isn't the only potential side effect of getting too much caffeine from tea or other sources. Caffeine can also cause difficulty sleeping, anxiety, nausea, vomiting, frequent urination, restlessness and tremors. If you habitually get a lot of caffeine in your diet, suddenly reducing your caffeine intake can cause withdrawal symptoms, such as headaches, irritability and drowsiness, according to MedlinePlus.