Kevin McCully, PhD
Kevin McCully, PhD, professor of kinesiology, Institute of Gerontology, University of Georgia, Athens, Georgia, and leader of a study published in Ultrasound in Medicine and Biology.
Many people assume that smoking an occasional cigarette isn’t harmful — but it is, a new study shows. In fact, it may be as harmful as smoking a lot.
Researchers at the University of Georgia utilized a new and more sophisticated type of ultrasound technology to investigate whether there is tangible harm from smoking occasionally. They recruited 18 healthy people in their 20s, half of whom were light smokers (less than a pack a week), while the other half said they had never smoked. Researchers used a new kind of ultrasound to measure how well the arterial blood vessels of the subjects dilated to accommodate changes in blood flow. In people with good heart health, the arteries dilate easily and effectively — if they don’t, it means there could be a blockage or vascular wall damage and in fact, “impaired flow mediated dilation” is among the earliest signs of cardiovascular disease.
Kevin McCully, PhD, a study coauthor, explained how the research was done. The light smokers were told to abstain from having any cigarettes for two days before they started testing. After these two days had passed, both groups were instructed to lie down and rest for 10 minutes. Blood pressure cuffs were pumped up to create arterial constriction for specific lengths of time, starting at 30 seconds all the way up to 10 minutes. Each time the cuff was removed and blood flowed back into the artery, an ultrasound device measured and recorded the increments in the artery’s dilation.
Researchers had expected the flow-mediated dilation numbers to be the same for both groups when they were resting — but they were not. In the light smokers, the flow-mediated dilation was 36% less responsive than in the nonsmokers.
Next the occasional smokers were asked to smoke two cigarettes, one immediately after the other. Again the blood pressure cuffs were put on and the results measured — this time the dilation of the occasional smoker’s arteries dropped another 24%. When you combine the resting rate and the post-two cigarette rate, the result is shocking — the arteries of occasional smokers become half as reactive as non-smokers after only two cigarettes… which is the same diminished reactivity as has been previously found in smokers who go through two packs of cigarettes a day, says Dr. McCully.
Further research will explore the question of how long that drop in dilation lasts in occasional smokers. But since this study shows the extreme impact of even light smoking, Dr. McCully recommends quitting — it’s just not worth it.