Vaping and Exercise: What E-Cigarettes Actually Do to Respiratory Function and Training Performance

The narrative around vaping as a harm reduction tool compared to combustible cigarettes is legitimate — switching from cigarettes to e-cigarettes reduces exposure to most of the combustion products (polycyclic aromatic hydrocarbons, carbon monoxide, formaldehyde from incomplete combustion, tar) that produce most of cigarette smoking's lung and cardiovascular damage. For current smokers who cannot quit nicotine entirely, switching to vaping is likely beneficial.

This is different from the claim that vaping is harmless. It is not. And for people who have never smoked — which includes many young people who have started vaping — the baseline comparison is not cigarettes but no inhaled aerosol at all.

The Aerosol Chemistry

E-cigarette aerosol is not steam. It contains:

• Propylene glycol and vegetable glycerin: The carrier liquids; when aerosolized, can irritate the respiratory epithelium; at high heat or with flavor additive contamination, degrade to acrolein and formaldehyde
• Nicotine: Unchanged from cigarette nicotine; same nicotinic acetylcholine receptor effects; same addiction profile; same cardiovascular effects (sympathetic activation, blood pressure increase, elevated heart rate)
• Flavoring compounds: The FDA has not evaluated inhaled safety of most flavor compounds; diacetyl (artificial butter flavor) causes bronchiolitis obliterans ("popcorn lung"); other flavoring compounds have uncertain inhalation profiles
• Ultrafine particles: The aerosol contains metal particles from the heating coil (nickel, chromium, tin) and fine particles small enough to deposit in alveoli

The Respiratory Function Evidence

> 📌 Chaumont et al. (2018) assessed vascular function in young healthy adults before and after acute e-cigarette use and found significant impairments in endothelial function (flow-mediated dilation decreased) and increased arterial stiffness — comparable in magnitude to findings after conventional cigarette smoking. [1]

Specific effects documented by the research literature:

• Endothelial dysfunction: Acute aerosol exposure reduces endothelial NO production (the vasodilation mechanism discussed in the arginine/citrulline context)
• Airway inflammation: Chronic vaping produces histological inflammatory changes in airway epithelium analogous to early-stage bronchitis
• Reduced exercise capacity: Studies comparing matched vapers against non-vapers show reduced VO₂max and exercise tolerance; the magnitude is smaller than combustible cigarettes but present

Vaping During Active Training

The exercise physiology concern:

• Nicotine's cardiac effect: acutely increases heart rate and blood pressure — not favorable during high-intensity training
• The endothelial function impairment reduces NO-mediated vasodilation during exercise, impairing blood flow to working muscles
• Propylene glycol in the aerosol has been associated with airway reactivity in occupational settings; in exercise conditions with high ventilation rates, larger aerosol volumes pass through the airway

The net effect: some measurable impairment in cardiovascular efficiency and exercise tolerance; less severe than combustible cigarettes but not negligible for performance-focused training.

---

Key Terms

• Diacetyl (2,3-butanedione) — the artificial butter flavoring compound associated with bronchiolitis obliterans ("popcorn lung") in occupational inhalation exposure; found in some e-cigarette flavors; banned by responsible manufacturers but inadequately regulated
• Endothelial dysfunction — reduced endothelium-dependent vasodilation, primarily from impaired nitric oxide production; produced by both cigarette smoke and e-cigarette aerosol; the earliest measurable vascular pathology on the cardiovascular disease trajectory
• VO₂max — maximal oxygen uptake during exercise; the gold standard measure of cardiovascular fitness; reduced in chronic vapers compared to matched non-vapers in controlled studies, though less severely than in cigarette smokers
• Ultrafine particles — particles less than 100nm in diameter; capable of deep alveolar deposition and systemic circulation entry; generated in e-cigarette aerosol from both the base liquid atomization and metal coil heating; the mechanism of lung cell toxicity from e-cigarette aerosol

---

Scientific Sources

• 1. Chaumont, M., et al. (2018). Differential effects of e-cigarette on microvascular endothelial function, arterial stiffness and oxidative stress: A randomized crossover trial. Scientific Reports, 8(1), 10378. PubMed