Researchers found that drinking a cup of caffeinated coffee significantly improved blood flow in the fingers of 27 healthy adults.
Measuring blood flow in the finger provides an indication of how well the body's smaller blood vessels are functioning. Comparing normal-strength coffee with decaf, the caffeinated version increased blood flow by 30% over a 75-minute period.
Professor Masato Tsutsui, a heart expert from the University of the Ryukyus in Okinawa, Japan, said: "This gives us a clue about how coffee may help improve cardiovascular health."
He presented the findings at the American Heart Association's Scientific Sessions meeting in Dallas, Texas.
The study participants were all people aged from 22 to 30 who did not regularly drink coffee. A laser technique was used to study blood circulation in the finger on a microscopic level non-invasively.