Young chronic e-cigarette users display cardiopulmonary abnormalities during exercise and blunted recruitment of pulmonary diffusing capacity

Figures

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  Figure 1. A, Exercise capacity, as evaluated by peak rate of oxygen consumption relative to body mass (V˙O2, mL/kg/min) in E-CIG and control participants. B, Ventilatory efficiency, represented by the ventilatory equivalent for CO2 production (V˙E/V˙CO2 nadir), during exercise in E-CIG and control participants. Square symbols denote V˙E/V˙CO2 nadir values exceeding predicted upper limit of normal. Data are presented as individual values and marginal means ± SE, adjusted for age, height, sex, and fitness. n = 20 per group. Bold indicates significant difference (P < .05). E-CIG = participants with e-cigarette exposure; V˙E = minute ventilation; V˙CO2 = CO2 output; V˙O2peak = peak rate of oxygen consumption.

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  Figure 2. Exertional dyspnea responses to submaximal exercise relative to workload (A), exertional dyspnea responses to submaximal exercise relative to V˙E (B), and operating lung volume responses (C) during submaximal exercise in E-CIG and control participants. Data are expressed as marginal means ± SE, adjusted for age, height, sex, and fitness. n = 20 per group. Bold indicates significant difference (P < .05). E-CIG = participants with e-cigarette exposure; EILV%TLC = end-inspiratory lung volume as a percentage of total lung capacity; EELV%TLC = end-expiratory lung volume as a percentage of total lung capacity; V˙E = minute ventilation.

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  Figure 3. Change (Δ) in Dlco, VC, and DM from the upright to supine posture in e-cigarette vs control groups. Data are presented as individual values and marginal means ± SE, adjusted for age, height, sex, and fitness. E-CIGs, n = 16; control, n = 17. Bold indicates significant difference (P < .05). Dlco = pulmonary diffusing capacity for carbon monoxide; DM = pulmonary membrane diffusing capacity; E-CIG = participants with e-cigarette exposure; VC = pulmonary capillary blood volume.