Tea drinkers, this includes you.

By Betty Gold
Updated February 26, 2020
Advertisement

If you rely on caffeine to wake you up and keep your energy going throughout the day, you aren't alone. Whether it's in coffee, tea, or soft drinks, caffeine is the most widely used pharmacologically active substance in the world: it’s consumed by more than 80 percent of people in most countries around the globe.

And real talk, we’re all probably taking in a lot more caffeine than we realize. The average cup of coffee is around 100 milligrams of caffeine per serving, soda is typically 50 milligrams, and energy drinks contain as much as 250 milligrams per serving. Even a chocolate bar can have more than 30 milligrams of caffeine.

According to Roshini Malaney, DO, a board-certified cardiologist at Manhattan Cardiology in New York City, everyone metabolizes—or breaks down—caffeine differently. “On average, the maximum concentration of caffeine in your body typically reaches its peak one hour after eating or drinking something caffeinated,” she says. If you drink a cup of coffee every morning, its effects will last in your body for an average of five hours. But if you consume several doses of caffeine throughout the day, the caffeine concentration is normally highest in the late afternoon and lowest upon awakening in the morning (which is why we need and really feel that initial cup of coffee in the morning). “However, any effects on the cardiovascular system can last between 10 and 60 hours,” Dr. Malaney says.

The effect caffeine has on heart health is hugely dependent upon how much you consume, the source, and the regularity.

So how much caffeine is too much caffeine for optimal heart health? According to Dr. Malaney, to stay on the safe side, two cups of coffee a day or less is generally OK, and more than four cups is not healthy. (We know caffeine sources vary, as do the size of coffee cups—if you're monitoring your overall caffeine intake, remember to stay under a 400 milligram limit.)

Here’s the doctor's full breakdown of the three main ways caffeine can impact your cardiovascularsystem.

Blood Pressure

Caffeine can raise blood pressure by as much as 10 mmHg in those that do not routinely drink coffee. (The increase in blood pressure can be more pronounced in those with underlying high blood pressure, and in older adults.) Consistent with this is that there can be a mild reduction in blood pressure when habitual coffee drinkers either abstain from coffee or switch to decaffeinated coffee. “Caffeine stimulates sympathetic activity in our brains, which is our fight or flight response. This ultimately causes our blood vessels to constrict,” Dr. Malaney says.

Cholesterol

Most studies have shown no adverse effects of caffeine or filtered coffee intake on cholesterol levels. However, non-filtered coffee (which contains coffee lipid compounds that are typically removed by a paper filter) may cause a slight elevation LDL—the ‘bad’ cholesterol—and total cholesterol. If heart hearth is a serious concern for you, it may be smart to avoid unfiltered coffee (like French press).

Palpitations

Those who are sensitive to caffeine can develop symptoms of palpitations after caffeine intake. In addition, there are case reports of other abnormal heart rhythms who have underlying heart disease.

Just Don't Go Overboard

Regardless, if you are a coffee lover, consuming small to moderate amounts of caffeine or caffeinated beverages—less than four cups of coffee per day or less than 400 milligrams of caffeine—has not been associated with causing or worsening cardiovascular disease. According to a study published in the Journal of the American Heart Association, regular consumption does not disrupt your heart's rhythm enough to create the dangerous irregular pattern known as atrial fibrillation. “Clinical recommendations advising against the regular consumption of caffeinated products to prevent disturbances of the heart’s cardiac rhythm should be reconsidered, as we may unnecessarily be discouraging consumption of items like chocolate, coffee, and tea that might actually have cardiovascular benefits,” said senior study author Gregory Marcus, MD, MAS, a UCSF Health cardiologist and director of clinical research in the UCSF Division of Cardiology. “Given our recent work demonstrating that extra heartbeats can be dangerous, this finding is especially relevant.”

Bottom Line

For optimal heart health, caffeine in moderation is key, says Dr. Malaney, who stands behind the 400 milligram-a-day limit stated above. “Also, it’s also worth noting that coffee consumption has actually been associated with a mildly lower incidence of stroke,” she adds. The Nurses’ Health Study found that women who consumed at least four cups of coffee per day had a significant 20 percent lower risk of total stroke than those who seldom (less than one cup per month) drank coffee.

The doctor also recommends you see your doctor if you notice any symptoms that occur with caffeine intake. And if you have any other risk factors for heart disease (such as high blood pressure, high cholesterol, or smoking), you should be evaluated by a cardiologist.