Chronic e-cigarette use in young adults is associated with reduced cardiopulmonary function at rest and during exercise

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E-cigarette aerosols produce contaminant particles that have the potential to impair cardiopulmonary function. However, the current understanding of the impact of e-cigarette use on cardiopulmonary function remains inconclusive. Exercise represents a stress on the cardiopulmonary system and may help identify cardiopulmonary dysfunction in chronic e-cigarette users. Consequently, the purpose of this study was to investigate if e-cigarette users exhibit cardiopulmonary abnormalities under physiological stress of exercise. To further investigate pulmonary vascular responses, the secondary purpose of the study was to examine how diffusing capacity (DLCO), pulmonary capillary blood volume (VC), and membrane diffusing capacity (DM) respond to positional changes, as the transition from the upright to supine position should increase DLCO, VC, and DM, secondarily to increased perfusion pressure. We hypothesized that e-cigarette users would exhibit impaired cardiopulmonary function during exercise and reduced pulmonary vascular responsiveness to postural changes. Six chronic e-cigarette (e-cig) users (age: 24±5yrs, 5±2 years of e-cigarette use) with <5 pack years of traditional cigarette smoking history and six non-smoking controls who were age-, height-, and sex-matched completed two experimental trials. Day 1: Pulmonary function test and cardiopulmonary exercise test. Day 2: multiple fraction of inspired oxygen DLCO technique to quantify DLCO, VC, and DM at rest in the upright and supine positions. Resting pulmonary function was not significantly different between groups. The change in DLCO from upright to supine was significantly lower in e-cig users compared to controls (Control: 7.61±2.32 ml/min/mmHg vs. E-cig: 3.17±2.09 ml/min/mmHg; p=0.01), due to a smaller change in VC ( p=0.03), which suggests reduced pulmonary vascular distention in e-cig users. V̇O2peak was significantly lower in e-cig users compared to controls (Control: 4.4±1.2 L/min vs. E-cig: 2.6 ±0.7 L/min; p=0.01). E-cig users exhibited significantly elevated V̇E/ V̇CO2nadir ( p=0.02) indicating worse ventilatory effciency, and greater dyspnea relative to power output ( p=0.02) compared to controls. Preliminary findings suggest that e-cigarette use is associated with normal resting lung function but reduced pulmonary vascular distensibility. Further, e-cigarette users demonstrate ventilatory ineffciency and greater exertional dyspnea along with exercise intolerance. Canadian Institutes of Health Research. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.