Why Limiting Your Coffee Intake Can Be Beneficial If You Have Severe Hypertension

For many people, brewing a piping hot cup of coffee upon waking up is the highlight of their morning. As the day goes on, however, it's easy to reach for another cup or two to sustain our energy. In fact, the National Coffee Association's 2020 National Coffee Data Trends (NCDT) report reveals that in the U.S., coffee lovers drink, on average, a little over three cups of java daily. However, a new study published in the Journal of the American Heart Association (JAHA) shows that doing so may pose a significant risk to those with severe hypertension.

According to the U.S. Centers for Disease Control and Prevention (CDC), hypertension affects 47% of American adults. A diagnosis of hypertension means that a person's blood pressure is above the normal range. Having high blood pressure can leave one more susceptible to stroke and cardiovascular disease, both of which continue to be top causes of death across the country. As per the study, researchers followed over 18,600 participants in Japan — at a starting age range of 40 through 79 — over the course of an average 18.9-year period. Using a series of self-reported questionnaires, as well as health exams, researchers found that participants with severe hypertension who drank two or more cups of coffee on a daily basis were twice as prone to cardiovascular disease mortality than non-coffee drinkers.

Participants were deemed as having either optimal and normal blood pressure, high-normal blood pressure, grade 1 hypertension, or grade 2 to 3 hypertension (severe hypertension), as per the study. While the risk of death due to cardiovascular disease was increased amongst participants with grade 2 or 3 hypertension who drank two or more cups of coffee per day, this relationship was not observed for those with grade 1 hypertension. Those with normal or high-normal blood pressure also seem to be unaffected. Although caffeine can negatively affect heart health by increasing blood pressure, the researchers noted that heavy coffee drinkers in the study also tended to smoke cigarettes, drink alcohol, eat less greens, and have higher total cholesterol levels.

Researchers also looked at the effects of a different caffeinated beverage on cardiovascular risk in participants with and without hypertension: green tea. Study findings showed no link between drinking green tea and increased risk of cardiovascular disease mortality, regardless of participant blood pressure level. Similarly, drinking one cup of coffee and one cup of green tea within the same day was also shown to have no effect on the risk of death from heart disease across participant groups, reports Healthline.

Although further research is needed, the study team emphasized the importance of individuals with severe hypertension limiting excess coffee consumption.