Effects of Acute Vaporized Nicotine in Non-Tobacco Users at Rest and during Exercise

Smokers, and even non-smokers, may utilize vaporized nicotine delivered by electronic cigarette (EC) due to the perception that EC are "healthier" than traditional tobacco cigarettes. The effects of vaporized nicotine delivered by EC on resting blood pressure (BP) and resting metabolic rate (RMR), or BP and aerobic power during exercise have not been studied. This investigation tested the effects of acute vaporized nicotine inhalation by EC on resting BP and RMR and cycle exercise BP, metabolic responses, and aerobic power in young, normotensive non-smokers. Using a double-blind design, 20 subjects (10 female) participated in two randomized trials: placebo (0 mg nicotine) or nicotine (18 mg nicotine). Participants inhaled from EC once every 30 s for 10 min (20 inhalations total). RMR was assessed 40 min later by indirect calorimetry followed by an incremental cycle test. RMR was not different between trials (p=0.79). Compared to the placebo, resting diastolic pressure (DBP) was 3 mmHg higher with nicotine (p=0.04). VO_2peak was not different between the nicotine trial (2.3±0.8 L•min^-1) and placebo (2.3±0.7 L•min^-1) trials (p=0.77), and W_max was also similar between nicotine (201.0±53.8 W) and the placebo (204.8±57.8 W) (p=0.29). During the cycle exercise test, average DBP was higher following nicotine use compared with placebo trial (p=0.05), and exercise DBP_peak after nicotine (79.4±7.6) was significantly higher than placebo (74.9±8.3 mmHg) (p=0.02). Resting systolic blood pressure (SBP) was 3.7 mmHg lower for nicotine trial (p=0.04) but no SBP treatment effect was observed during exercise (p=0.14). Our results show that acute vaporized nicotine inhalation via EC increases resting and exercise DBP but does not affect RMR or cycle aerobic power in young, normotensive non-smokers.