A new study from Canada suggests that even light smoking in otherwise healthy young people damages the arteries, reducing their bodies’ ability to deal with physical stress such as exercise, running to catch a bus or climbing stairs.

The study was led by Dr Stella Daskalopoulou, an internal medicine and vascular medicine specialist at McGill University Health Centre (MUHC) in Montreal, Quebec, who presented it at the Canadian Cardiovascular Congress 2009 that is taking place 24 to 29 October in Edmonton, Alberta. The event is co-hosted by the Heart and Stroke Foundation and the Canadian Cardiovascular Society.

In fact, Daskalopoulou and colleagues showed that even one cigarette led to serious adverse effects in young adults: it increased the stiffness of the arteries of otherwise healthy 18 to 30 year olds by 25 per cent, she told the conference.

Smoking helps plaque accumulate in the arteries, leading to a higher risk of blood clots, less oxygen in the blood, and higher blood pressure. It also makes the heart work harder and nearly doubles the risk of ischemic stroke (due to inadequate blood flow).

Also, when arteries get harder, the heart has to work harder to pump the same amount of blood around, and the stiffer the artery, the higher the risk of heart disease or stroke.

Daskalopoulou told delegates:

“Young adults aged 20-24 years have the highest smoking rate of all age groups in Canada.”

“Our results are significant because they suggest that smoking just a few cigarettes a day impacts the health of the arteries. This was revealed very clearly when these young people were placed under physical stress, such as exercise,” she explained.

For the study, Daskalopoulou and colleagues compared the arterial stiffness of young smokers who smoked about five or six cigarettes a day to that of non-smokers. The median age of the participants was 21.

They measured the participants’ arterial stiffness in three arteries, both at rest and then after an arterial stress test, using a new but not well established method called applanation tonometry. The three arteries were the radial (wrist), carotid (neck) and femoral (groin) arteries.

The “arterial stress test” was a bit like a cardiac stress test that measures the heart’s response to exercise, except in this case Daskalopoulou and colleagues measured the arteries’ response to exercise. Daskalopoulou said that:

“In effect we were measuring the elasticity of arteries under challenge from tobacco.”

The participants first underwent an initial arterial stress test to establish a baseline measurement for both smokers and non-smokers who were asked to abstain for 12 hours before the test. After that first test, the smokers were invited back and asked to smoke one cigarette each and then take the test again.

The exercise was repeated one more time, except this time the smokers were asked to chew a piece of nicotine gum before taking the stress test.

Non-smokers also did the arterial stress test to establish their arterial stiffness levels after exercise.

The researchers found that:

  • After exercise, the arterial stiffness of non-smokers fell by 3.6 per cent.
  • For smokers however, the pattern was reversed: after exercise (without smoking) their arterial stiffness went up by 2.2 per cent.
  • After nicotine gum, it went up 12.6 per cent, and after smoking just one cigarette it went up by 24.5 per cent.

Interestingly, said Daskalopoulou, arterial stiffness was the same in smokers and non-smokers at rest.

Daskalopoulou said that:

“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.”

“It seems that this compromise to respond to physical stress occurs first, before the damage of the arteries becomes evident at rest,” she explained.

Dr Beth Abramson from the Heart and Stroke Foundation said that:

“More than 47,000 Canadians will die prematurely each year due to tobacco use, which often starts in the teen years.”

“We know that over 90 per cent of teenagers who smoke as few as three to four cigarettes a day may be trapped into a lifelong habit of regular smoking, which typically lasts 35 to 40 years,” she added.

Abramson said this study confirmed the importance of education, prevention and legislation, such as the recent passing of Bill C-32, Cracking Down on Tobacco Marketing Aimed at Youth Act.

Source: Heart and Stroke Foundation of Canada.

Written by: Catharine Paddock, PhD