Drinking caffeinated coffee boosts blood flow

A new study has revealed that the caffeine in a cup of coffee might perk up your blood vessels, thereby improving your cardiovascular health.

A study of 27 healthy adults showed, for the first time, that drinking a cup of caffeinated coffee significantly improved blood flow in a finger, which is a measure of how well the inner lining of the body's smaller blood vessels work.

Specifically, participants who drank a cup of caffeinated coffee had a 30 percent increase in blood flow over a 75-minute period compared to those who drank decaffeinated coffee.

"This gives us a clue about how coffee may help improve cardiovascular health," lead researcher Masato Tsutsui from the pharmacology department at the University of the Ryukyus in Okinawa, Japan.

Study participants were people who did not regularly drink coffee, ranging in age from 22 to 30. On one day, each participant drank one five-ounce cup of either regular or decaffeinated coffee.

Then researchers measured finger blood flow with laser Doppler flowmetry, a non-invasive technique for gauging blood circulation on a microscopic level. Two days later, the experiment was repeated with the other type of coffee. Neither the researchers nor the participants knew when they were drinking caffeinated coffee.

The researchers noted blood pressure, heart rate, and vascular resistance levels. They also took blood samples to analyze levels of caffeine and to rule out the role of hormones on blood vessel function.

Compared to decaf, caffeinated coffee slightly raised participants' blood pressure and improved vessel inner lining function. Heart rate levels were the same between the two groups.

The study was presented at the American Heart Association's Scientific Sessions 2013.