This report highlights that such claims are difficult to make in light of the fact that “nicotine is an alkaloid which raises blood pressure and heart rate, and induces vasoconstriction through mechanisms such as catecholamine releases and endothelial dysfunction.”
Typically, previous studies have looked at the impact of submerging cell cultures in a swimming pool of liquid. This differs in that it is a placebo-controlled, randomized, single blind three-period crossover study, using 25 healthy occasional tobacco smokers who were selected on the basis of their excellent vaping tolerance.
The subjects underwent three stages:
- Vaping without nicotine
- Vaping with nicotine; and
The subjects took twenty-five puffs lasting 4 seconds and using more than 1.5 ml of eliquid. Plus, importantly, the team opted to use currently popular equipment, set at 60W with 4Ω coil heads. The subjects vaped in “intense vaping conditions”, selected to maximise the “ability to detect any harmful effect of e-cigarette on microcirculation, arterial stiffness, hemodynamic parameters and oxidative stress.”
The team’s main findings: “In young and healthy tobacco smokers, acute exposure to high temperature vaporisation of a pharmaceutical grade nicotine free PG/GLY mix (50:50): (1) did not alter microcirculatory function as well as arterial stiffness and oxidative stress; (2) whereas vaping the same mix plus nicotine decreased microcirculatory endothelial-dependent function, increased arterial stiffness, provoked a sustain raise in blood pressure and heart rate and increased plasma myeloperoxidase.”
They note that the sample size was small and that “studies of nicotine medications indicate that the risks of nicotine without tobacco combustion are low compared to cigarette smoking.” But, the paper is quick to point out that the team is reluctant to give high temperature vaping the all clear, as “other important target organs such as the upper and lower airways were not assessed in this study.”
They also point out that the results might not be mirrored in other possible groups such as heavy or non-smokers. Plus, people with a higher cardiovascular risk or lung disease were not studied and this type of vaping could impact more greatly on them.
Finally, they highlighted that their investigation reproduced the impact of vaping at high intensity for a short time, whereas the bulk of vapers take 120–235 puffs in a day over a number of sessions and consume a mean of 4 ml e-liquid per day.
The team concluded: “Our study reveals the new finding that high temperature e-cigarette vehicles vaporization and inhalation in occasional smokers does not alter micro and macrovascular endothelial function, as well as oxidative stress. These effects are merely attributable to the nicotine present in the e-liquid.”
Source: Differential Effects of E-Cigarette on Microvascular Endothelial Function, Arterial Stiffness and Oxidative Stress: A Randomized Crossover Trial by Chaumont et al DOI: 10.1038/s41598-018-28723-0