BALTIMORE -- Some people enjoy smoking and coffee together, but the combination appears to have a harmful effect on arteries and blood flow, according to a new study.

Researchers believe that the combination of the two actions is worse than if one combined the effects of each practice individually. They said the negative effects are both immediate and long-term.

The study appears in the Nov. 2 issue of the Journal of the American College of Cardiology.

"Our study confirms that smoking has an additional unfavorable effect and that heavy coffee consumption may pose an additional risk," said Dr. Charalambos Vlachopoulos, of the Athens Medical School and Hippokration Hospital in Athens, Greece.

Vlachopoulos recommends that people quit smoking, at least, while drinking coffee or other caffeine-containing drinks.

This research had two parts: a study of 14 people on the immediate effects of smoking and caffeine, and a study of 160 people that looked for signs of long-term consequences.

In each study, the researchers evaluated the stiffness of the aorta -- the largest artery leading from the heart -- and arterial blood flow. Each of these are factors in cardiovascular disease risk and high blood pressure.

Vlachopoulos said that this study involved healthy participants, so the researchers cannot say with certainty whether smoking and caffeine have the same effects in people with heart disease.

Study Abstract