Does coffee affect your blood pressure?

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If you can't get out the door in the morning without a cup of dark roast, you're not alone. According to the National Coffee Association's spring 2022 trend report, Americans drink about two cups of coffee each, daily—that's 517 million cups of coffee total per day. But is your caffeine intake impacting your blood pressure? It's a natural question, considering the fact that caffeine can make our tickers go pitter-patter or cause a racing heart rate. Ahead, a cardiologist explains whether your morning cup of coffee can impact your blood pressure.

Related: How to Make Your Favorite Coffee Drinks at Home

How Coffee Affects Blood Pressure Readings

A blood pressure reading consists of two numbers, each of which measures the pressure against your arteries as your blood is moving through them; systolic blood pressure is the reading when your heart beats, and diastolic blood pressure is the reading between beats. According to the CDC, a normal blood pressure reading falls under a systolic reading of 120 and a diastolic reading of 80.

Coffee and other caffeinated beverages cause the muscles of the arterial walls to tighten and the blood vessels' diameter to decrease—a process called vasoconstriction—which raises blood pressure, notes cardiologist Dr. Seamus Whelton of Johns Hopkins Medicine. But studies have shown that blood pressure spikes from coffee last only a few hours. Habitual coffee drinkers likely develop a tolerance. In fact, one study showed that after two weeks of drinking coffee, the blood pressure increase had vanished. However, says Dr. Whelton, if you are keeping a close watch on your blood pressure, you should refrain from caffeine for at least half an hour before taking your readings.

Coffee and Hypertension

Consistently elevated high blood pressure, called hypertension, stems from a variety of factors, including diseases such as diabetes and lifestyle factors such as obesity, poor diet, and smoking. It can also contribute to your risk of heart attack, stroke, and dementia. But caffeine doesn't appear to worsen the condition: In 2017, Expert Review of Cardiovascular Therapy published a report on studies that associated coffee with hypertension and cardiovascular disease, noting that "recent, well controlled studies have demonstrated either a neutral or beneficial effect of moderate coffee consumption (three to four cups/day) on blood pressure, cardiovascular disease, heart failure, cardiac arrhythmias, or diabetes mellitus." (If you are managing hypertension, discuss your caffeine intake with your doctor.)

Healthy Coffee Consumption

Coffee has established health benefits—"consuming coffee in moderation has been associated with a reduced risk of heart failure, type II diabetes, and coronary heart disease," says Dr. Whelton—but doctors recommend keeping your intake to two or three cups per day (and skipping the sweetener, cream, syrups, and other add-ins that can spike your sugar intake and add extra calories). And don't reach for your extra-large mug: "It is important to pay attention to not only the number of cups of coffee you drink per day, but also the portion in each serving," explains Dr. Whelton. "Some popular coffee shops have serving sizes with 24 or more ounces of coffee, which is roughly equivalent to four cups of coffee in a single serving."