E-cigarettes, Nicotine Inhaler, and Blood Vessel Function

Participants will have an acute exposure on 4 occasions1) e-cigarette with nicotine, 2) e-cigarette without nicotine, 3) nicotine inhaler, 4) sham control and undergo ECG recording for heart rate variability, endothelial function measurement using ultrasound ("FMD") and blood tests for oxidative stress markers.