Vaping High vs. Low Nicotine E-Liquid

This is a within-subjects, crossover design of advanced electronic cigarette users in which we will examine nicotine pharmacokinetics, subjective effects, daily nicotine intake and nicotine titration, short-term cardiovascular effects, and toxicant exposure when participants are using low vs. high nicotine e-liquids. Hypothesis 1: E-cigarette users will titrate their intake of nicotine such that they will inhale fewer aerosol toxicants and suffer less harm to health when using higher vs. lower nicotine content e-liquids. Hypothesis 2: Compared to low nicotine, high nicotine e-liquid use will have similar cardiovascular effects throughout the day (due to compensatory behavioral changes), with similar effects on heart rate, blood pressure, and catecholamine release. Hypothesis 3: Exposure to volatile organic compounds (VOCs) will be lower when vaping high nicotine e-liquids compared to low nicotine e-liquids.