Vascular Function and Cardiorespiratory Fitness in Adults Who Use Nicotine Vapes

Importance The rising use of nicotine vapes among young adults who have never smoked combustible tobacco raises concerns regarding potential early cardiovascular and respiratory effects in an otherwise low-risk population. Objective To determine whether regular daily nicotine vape use is associated with altered vascular function and cardiorespiratory fitness in young adults without established cardiovascular risk factors. Design, Setting, and Participants This was a cross-sectional, single-center, laboratory-based physiological assessment study conducted between July 2023 and April 2025 among young adults without known cardiovascular disease or major risk factors. Based on self-report and verification of smoking status, participants were stratified into 3 groups: adults who exclusively used nicotine vapes, adults who used combustible cigarettes, and tobacco- and nicotine vape–naive individuals. Data analysis was performed from September 2023 to April 2025. Exposure Regular daily use of nicotine vapes or combustible cigarettes. Main Outcomes and Measures Primary outcomes included vascular function, assessed by flow-mediated dilation (FMD) and carotid artery reactivity (CAR), and cardiorespiratory fitness, assessed through ventilatory, metabolic, and cardiac responses during maximal cardiopulmonary exercise testing. Secondary measures included spirometry results and physical activity. Results Fifty-eight young adults (mean [SD] age, 26 [7] years; 30 [52%] female) were included, among whom 17 exclusively used nicotine vapes, 19 used combustible cigarettes, and 22 were tobacco and nicotine vape naive. Lung function and physical activity levels did not differ significantly across groups. FMD and CAR were lower both in adults who used nicotine vapes (mean [SD] FMD, 5.5% [3.4%]; mean [SD] CAR, 0.6% [5.3%]) and in adults who used combustible cigarettes (mean [SD] FMD, 4.4% [2.9%]; mean [SD] CAR, −1.4% [5.3%]) compared with tobacco- and nicotine vape–naive individuals (mean [SD] FMD, 8.3% [3.4%]; mean [SD] CAR, 4.7% [3.2%]). Peak oxygen uptake was lower in adults who used nicotine vapes compared with tobacco- and nicotine vape–naive individuals but did not differ significantly between combustible cigarette and naive groups; minute ventilation and cardiac output were lower in both nicotine use groups. Conclusions and Relevance Regular daily nicotine vape use in young adults who have never smoked combustible tobacco was associated with lower vascular function and cardiorespiratory fitness. These findings highlight the need for longitudinal studies to determine long-term clinical implications.