PURPOSE:The purpose of the study was to examine the effects of electronic cigarettes (e-cigarettes) on lung function, aerobic capacity, and arterial stiffness. METHODS: A total of 19 subjects (11 males, 8 females; age=20.7+2.9 yrs; mass=69.5+13.8 kg; height=170.7+9.5 cm) participated in the study and were split into three groups: Neversmokers/vapers (NON; n=11), short-term e-cigarette users (ST; n=3), and long-term e-cigarette users (LT; n=5). ST reported vaping 28.3+10.4 pods for 7.7+3.2 months compared to the LT who reported vaping 220.0+83.7 pods for 27.2+7.6 months. Subjects completed a familiarization session followed by a testing session. RESULTS: No significant mean differences (all ps>.05) were found to exist between NON, ST, and LT for FVC, FEV1, FEV1/FVC, PEF, AIx, AIx75, or VO2peak. The highest VO2peak values were obtained within NON (49.75+9.55 mL•min -1 •kg -1 ) compared to the ST (45.70+0.52 mL•min -1 •kg -1 ) and LT (39.51+10.37 mL•min -1 •kg -1 ). A large effect (d=1.04) was identified between NON and LT and when comparing all groups, indicating the variation in VO2peak values may be due to e-cigarette usage. NON also displayed the largest measured lung volumes (FVCNON=4.95+1.15 L) on average compared to both ST (FVCST=4.06+1.15 L) and LT (FVCLT=4.3+0.87 L), which were identified by large effects (10.9%, 10.3%, and 14.8%) for FVC, PEF, and FEV1, respectively. CONCLUSION: Vaping e-cigarettes (< 3 years) was found to have no major impact on lung function, arterial stiffness, or aerobic capacity within e-cigarette only users. Data collection was terminated early due to the COVID-19 pandemic resulting in small, unequal groups. The trends identified are representative of physiological changes that may occur, but the extent and overall impact of changes are still undetermined. The subject with the longest self-reported e-cigarette usage duration (36 months; 200 pods) displayed elevated levels of augmentation index (AIx75=23%). NON displayed the largest measured lung volumes and highest recorded VO2peak values, on average. Small variations were identified, yet the potential consequences and effects of prolonged, chronic use of e-cigarettes, specifically on the cardiorespiratory health of humans and the impact on performance capabilities, remains unclear.