Oct. 28 (HealthDay News) -- Smoking just one cigarette stiffens the arteries of young adults by 25 percent, says a new study.

The stiffer a person's arteries, the greater their risk for heart disease or stroke, noted researcher Dr. Stella Daskalopoulou, an internal medicine and vascular medicine specialist at McGill University Health Center in Montreal.

She measured arterial stiffness in smokers and non-smokers, ages 18 to 30, at rest and after exercise. To establish a baseline measurement, the smokers, who smoked five to six cigarettes a day, were asked to refrain from having a cigarette for 12 hours before their first exercise test. Before the second exercise test, smokers were allowed to have one cigarette. Before the final test, they were asked to chew a piece of nicotine gum.

After exercise, arterial stiffness in non-smokers decreased 3.6 percent. But the smokers' arterial stiffness increased 2.2 percent after exercise. In smokers, arterial stiffness increased 12.6 percent after they chewed nicotine gum and 24.5 percent after they had one cigarette.

There was no difference in arterial stiffness between smokers and non-smokers at rest.

"Our results are significant because they suggest that smoking just a few cigarettes a day impacts the health of the arteries," Daskalopoulou said in a news release from the Heart and Stroke Foundation of Canada. "This was revealed very clearly when these young people were placed under physical stress, such as exercise."

"In effect, this means that even light smoking in otherwise young healthy people can damage the arteries, compromising the ability of their bodies to cope with physical stress, such as climbing a set of stairs or running to catch a bus," she said. "It seems that this compromise to respond to physical stress occurs first, before the damage of the arteries becomes evident at rest."

The study was to be presented Oct. 27 at the Canadian Cardiovascular Congress 2009.

SOURCE: Heart and Stroke Foundation of Canada, news release, Oct. 27, 2009