Contrary to widespread belief, scientific evidence suggests that regular coffee drinkers may have decreased risk of heart attack, heart disease, and stroke.
Drinking 3-5 cups of coffee per day may reduce cardiovascular disease (CVD) mortality risk by up to 21%. [Source]
Several studies link moderate caffeine consumption to lower risk of cardiovascular and all-cause mortality. Caffeine may also help prevent clogged arteries - a known risk factor for heart disease. [Source]
Recently, a 2016 report refuted the common misconception that caffeinated coffee caused irregular heart rhythms, which can lead to heart failure or dangerous heart rhythm disorders.
In light of this evidence, many members of the medical community are reconsidering previous recommendations to limit natural sources of caffeine. “We may unnecessarily be discouraging consumption of items like chocolate, coffee and tea that might actually have cardiovascular benefits," says Dr. Gregory Marcus, a cardiologist at the University of California San Francisco, who led the study. This sentiment is reflected in the favorable inclusion of coffee in the latest U.S. Dietary Guidelines.
More research is needed to fully understand coffee’s observed beneficial effects on heart health. A small study from Japan suggested that the caffeine in a cup of coffee might help your small blood vessels work better, which could ease strain on the heart. [Source]
However, most scientists believe that caffeine is unlikely to be solely responsible for the observed cardiovascular perks.