Systemic Lactate Elevation Induced by Tobacco Smoking during Rest and Exercise Is Not Associated with Nicotine.

Sri Sumartiningsih,Michal Starczewski,Setya Rahayu,Jung-Charng Lin,Eko Handoyo,Chia-Hua Kuo,Chin Leong Lim,Philip X Fuchs

doi:10.3390/ijerph19052902

Abstract

Lactate is a metabolite produced during anaerobic glycolysis for ATP resynthesis, which accumulates during hypoxia and muscle contraction. Tobacco smoking significantly increases blood lactate. Here we conducted a counter-balanced crossover study to examine whether this effect is associated with inhaling nicotine or burned carbon particles. Fifteen male smokers (aged 23 to 26 years) were randomized into 3 inhalation conditions: tobacco smoking, nicotine vaping, and nicotine-free vaping, conducted two days apart. An electronic thermal evaporator (e-cigarette) was used for vaping. We have observed an increased blood lactate (+62%, main effect: p < 0.01) and a decreased blood glucose (−12%, main effect: p < 0.05) during thermal air inhalations regardless of the content delivered. Exercise-induced lactate accumulation and shuttle run performance were similar for the 3 inhalation conditions. Tobacco smoking slightly increased the resting heart rate above the two vaping conditions (p < 0.05), implicating the role of burned carbon particles on sympathetic stimulation, independent of nicotine and thermal air. The exercise response in the heart rate was similar for the 3 conditions. The results of the study suggest that acute hypoxia was induced by breathing thermal air. This may explain the reciprocal increases in lactate and decreases in glucose. The impaired lung function in oxygen delivery of tobacco smoking is unrelated to nicotine.

Highlights

Blood lactate increased after tobacco smoking, nicotine-free vaping, and nicotine vaping to a similar extent (d = 1.1, main effect of time: p < 0.001)
Lactate accumulation after exercise was similar for all three conditions (d = 0.96, main effect of time, p < 0.001)
We found an increased blood lactate accumulation together with decreased blood glucose after nicotine-free vaping

Summary

Introduction

Tobacco smoking is a risk factor for all-cause mortality and impaired pulmonary function [1–4]. Nicotine is widely regarded as the main addictive component of tobacco during smoking [5]. Breathing smoke from nicotine-containing tobacco cigarettes (1–14 mg) [6] or electronic (E) cigarettes (3–19 mg/mL) increased heart rate and blood pressure [7–9]. A variety of carbon particles is generated during the burning process of tobacco leaves. Burned carbon particles and various chemicals in combination of thermal stress can cause edema and injury to the lower airway and alveoli [10].

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