Cardiovascular and metabolic acute effects of heated tobacco products in healthy smokers
Lea Strohm, Dominika Mihaliková, Alexander Czarnowski, Patrick Dittmann, Dominik Gillenkirch, Omar Hahad, Michael Molitor, Marin Kuntic, Philipp Lurz, Thomas Münzel, Andreas Daiber, Paul StammAbstract
Aims
Heated tobacco products (HTPs) are increasingly promoted as ‘reduced-harm’ alternatives to combustible cigarettes, despite delivering pharmacologically active nicotine and complex aerosols. Independent human data on their acute cardiovascular effects remain limited.
Methods and results
In this investigator-initiated, within-subject pre–post study, healthy adult smokers were supervised in their exposure to two consecutive HTP sticks (IQOS). Endothelial function was assessed by brachial artery flow-mediated dilation (FMD), along with haemodynamic parameters, venous blood gas and metabolic markers, and oxidative DNA damage measured by the comet assay. Acute HTP exposure resulted in a significant reduction in FMD, indicating rapid endothelial dysfunction. This was accompanied by an increase in systolic blood pressure, reductions in venous oxygen tension and saturation, and an increase in venous carbon dioxide, consistent with impaired tissue oxygenation. Methaemoglobin levels increased, reflecting oxidative modification of haemoglobin, while metabolic alterations in glucose and lactate suggested nicotine-mediated sympathetic and metabolic stress. Importantly, short-term HTP use induced significant oxidative DNA damage in peripheral blood cells. These effects occurred after a single, real-world exposure in otherwise healthy smokers.
Conclusion
Together, these findings demonstrate that HTPs are not biologically inert and that acute exposure is sufficient to trigger vascular dysfunction, systemic metabolic disturbance, and genotoxic stress. The results challenge claims of cardiovascular harm reduction and underscore that all nicotine-containing products remain relevant targets for cardiovascular prevention and regulation.