One Heated Tobacco Session, Visible Harm

Researchers at University Medical Center Mainz tested 30 otherwise healthy adult smokers, average age 34, before and after they used two tobacco sticks back-to-back in a tobacco-heating device. The team measured blood pressure, took blood samples and assessed vascular function with an ultrasound scan of the main artery in the right arm.

After that single session, systolic blood pressure increased by 3 mmHg and blood vessel function fell by 11%, measured through flow-mediated dilation, a standard test of how well an artery widens when blood flow increases. Venous oxygen saturation also dropped sharply, from about 71% to about 46%, which the researchers said pointed to reduced oxygen delivery around the body.

They also found an oxidative stress response and DNA damage in blood cells. For a product category often presented as a less harmful alternative to conventional cigarettes, that is a difficult result to wave away. The study does not settle long-term risk by itself, and it does not claim every effect is identical to smoking a cigarette. It does show that acute exposure is enough to produce immediate cardiovascular strain and cellular damage.

Lead researcher Dr. Lea Strohm said independent evidence on the immediate effects of heated tobacco products on cardiovascular health and the body more broadly has remained limited. In the source report, she said the findings challenge claims that these products are substantially less harmful to the cardiovascular system than conventional cigarettes.

Co-author Prof. Thomas Münzel put it even more bluntly, arguing that no nicotine-containing product should be considered safe for the heart and blood vessels, whether it is smoked, heated, vaped or otherwise absorbed.

That is the part likely to matter beyond this small study. Heated tobacco is often discussed in relative terms, safer than this, cleaner than that, as if the argument only needs a lower rung. The Mainz data does not answer every comparative question, but it does narrow the room for reassurance. Two sticks, one session, measurable harm.

The researchers said larger long-term studies are still needed to determine how long these effects last.