What vaping does to the body

Exposure to the complex chemical mixture in e-cigarette aerosol can adversely affect multiple organ systems throughout the body. While research is ongoing, particularly regarding long-term effects, significant evidence points to detrimental impacts on respiratory, cardiovascular, neurological, and other systems.

A. Respiratory Consequences

The lungs are the primary site of exposure to vape aerosol, and evidence indicates a range of adverse respiratory effects:

• Short-Term Irritation: Common immediate effects include coughing, shortness of breath, wheezing, irritation of the throat and eyes, headaches, and sometimes nausea.
• Inflammation and Cellular Damage: Inhaled particles and chemicals directly irritate and inflame lung tissues. Studies have demonstrated that the primary e-liquid solvents, PG and VG, are toxic to lung cells in laboratory settings. Chronic inflammation can lead to structural damage, including potential scarring (fibrosis) and narrowing of the airways.
• Exacerbation of Existing Conditions: There is moderate evidence linking vaping to increased frequency or severity of symptoms in individuals with pre-existing respiratory conditions. This includes increased coughing, wheezing, and exacerbations in individuals with asthma, particularly youth. Vaping may also worsen symptoms of COPD.
• Specific Lung Diseases: Certain severe lung conditions have been associated with vaping. Bronchiolitis obliterans (“popcorn lung”), characterized by irreversible scarring of the small airways, has been linked to exposure to the flavoring chemical diacetyl. Other reported conditions include various forms of pneumonia (such as lipoid pneumonia, potentially linked to inhaled oils in e-liquids, and eosinophilic pneumonia), interstitial lung diseases, and diffuse alveolar hemorrhage. Cases of collapsed lung (pneumothorax) have also been reported in vapers.
• EVALI (E-cigarette or Vaping Use-Associated Lung Injury): The 2019 outbreak highlighted the potential for severe, acute lung injury related to vaping. EVALI presented with symptoms including cough, shortness of breath, chest pain, fever, gastrointestinal issues (vomiting, diarrhea), and sometimes rapid respiratory failure requiring hospitalization. While the outbreak was strongly linked to vitamin E acetate, an additive used primarily in illicit THC-containing vape cartridges , it underscored the potential for inhaled substances in vape products to cause severe lung damage. The outbreak resulted in thousands of hospitalizations and dozens of deaths across the U.S..
• Increased Risk of Chronic Lung Disease: Longitudinal studies tracking individuals over time have begun to emerge. A significant finding from the large U.S. Population Assessment of Tobacco and Health (PATH) study indicated that e-cigarette users had a significantly increased risk of developing chronic lung diseases, including asthma, bronchitis, emphysema, or COPD, compared to non-users, independent of their smoking history. Importantly, individuals who engaged in dual use (vaping and smoking cigarettes concurrently) faced the highest risk, substantially greater than those using only one product. While some analyses focusing specifically on never-smokers found limited evidence of this association due to small sample sizes in early cohorts , the overall trend points towards vaping contributing to chronic respiratory conditions over time.

B. Cardiovascular Consequences

The cardiovascular system is also significantly affected by vaping, with effects observed both acutely and potentially chronically:

• Acute Hemodynamic Effects: Vaping typically causes an immediate increase in both heart rate and blood pressure. Meta-analyses confirm these acute effects compared to non-use. Comparisons with acute effects of smoking are complex; some studies suggest the heart rate increase might be slightly lower with vaping, while blood pressure effects appear similar or findings are inconsistent.
• Vascular Dysfunction: Accumulating evidence points to detrimental effects on blood vessel health. Studies report endothelial dysfunction, which is an impairment in the normal function of the cells lining the blood vessels, a key early step in the development of atherosclerosis (hardening of the arteries). Increased arterial stiffness (making arteries less flexible) and vasoconstriction (narrowing of blood vessels) have also been observed. Underlying mechanisms likely involve increased oxidative stress, inflammation within the blood vessels, and reduced production or availability of nitric oxide, a crucial molecule for maintaining vascular health. Some research suggests these effects may not solely be due to nicotine; flavorings and the physical act of inhaling irritants may also play roles. This indicates a complex pathophysiology where multiple components of the aerosol contribute to vascular harm, challenging the notion that vaping is benign for the cardiovascular system simply because it avoids combustion products like tar.
• Adverse Cardiovascular Risk Markers: Research has shown that the blood of chronic e-cigarette users contains elevated levels of certain biomarkers associated with increased cardiovascular risk. Interestingly, some of these markers differ from those typically elevated in traditional smokers, suggesting potentially distinct pathways of harm. For example, studies found that blood from vapers caused increased permeability in cultured blood vessel cells compared to blood from smokers or non-users.
• Association with Cardiovascular Events: Epidemiological studies have linked e-cigarette use with increased odds of experiencing serious cardiovascular events. Several analyses report a significantly higher risk of myocardial infarction (heart attack) among e-cigarette users compared to non-users. Some studies also suggest an increased risk of stroke. The risk appears particularly elevated for dual users; one large study found daily dual users had nearly five times the odds of a heart attack compared to non-users. However, it is important to note that some systematic reviews conclude there is currently limited evidence directly linking vaping to established clinical cardiovascular disease outcomes (like diagnosed coronary heart disease or long-term cardiac remodeling), emphasizing the need for longer-term follow-up studies.

C. Neurological and Mental Health Consequences

Nicotine’s effects on the brain are profound, especially during critical developmental periods:

• Impact on Adolescent Brain Development: The human brain continues to develop until about age 25. Nicotine exposure during adolescence and young adulthood can disrupt the maturation of brain circuits, particularly those involved in attention, learning, memory, mood regulation, and impulse control. This can lead to long-lasting deficits in cognitive function and emotional regulation.
• Cognitive Effects: Vaping, through nicotine exposure, may impair memory, concentration, and executive functions, potentially impacting academic performance and daily tasks.
• Increased Risk of Other Addictions: Nicotine exposure during adolescence can alter brain chemistry in ways that increase vulnerability to addiction to other drugs later in life. This “gateway” effect suggests that early nicotine dependence from vaping could have broader implications for substance use behaviors.
• Seizures: There have been reports submitted to regulatory agencies, such as the U.S. FDA, concerning seizures occurring in individuals after vaping, with reports most common among youth and young adults. While the exact cause is under investigation, high nicotine concentrations (“nicotine toxicity”) are suspected to play a role.
• Mental Health Associations: Studies consistently show an association between vaping among youth and young adults and mental health challenges, including increased symptoms of depression, anxiety, and stress. Some research also suggests links with ADHD symptoms. While the directionality of this relationship is complex (i.e., does vaping contribute to mental health issues, or do individuals with these issues self-medicate with nicotine?), there is concern that nicotine dependence itself acts as a stressor and that youth may initiate or continue vaping in an attempt to cope with anxiety or stress, thereby perpetuating a cycle of dependence and potentially worsening underlying issues.

D. Carcinogenic Potential

While cigarette smoking is unequivocally linked to numerous cancers due to the thousands of chemicals produced during combustion, the carcinogenic potential of vaping is still under investigation, primarily due to its shorter history of widespread use.

• Presence of Carcinogens: As established, e-cigarette aerosol is not free of carcinogens. It contains known cancer-causing agents such as formaldehyde, acetaldehyde, benzene, and tobacco-specific nitrosamines (TSNAs), although generally at lower levels than in cigarette smoke. Heavy metals like cadmium and nickel found in the aerosol also have carcinogenic potential.
• Biomarker Evidence of Cancer Risk: While long-term cancer outcome data is lacking, numerous studies using biomarkers provide concerning evidence. Research shows that exposure to e-cigarette aerosol is associated with biological changes relevant to cancer development. These include increased oxidative stress (an imbalance harmful to cells), DNA damage (mutations) and strand breaks, impaired DNA repair mechanisms, increased cellular apoptosis (programmed cell death) and necrosis (uncontrolled cell death), genotoxicity (damage to genetic material), and potentially promotion of tumor growth characteristics in cell models. Specific studies have documented DNA damage in cells lining the mouth and airways following vape exposure. These molecular and cellular changes represent crucial steps in the process of carcinogenesis. Although they do not constitute definitive proof that vaping causes cancer in humans, they provide strong biological plausibility for such a risk and serve as critical early warning signs. This evidence directly challenges assertions of vaping’s long-term safety and justifies a precautionary approach, particularly regarding preventing initiation among young people.
• Current Understanding of Cancer Risk: Based on current evidence, major health bodies conclude that while vaping likely poses a lower cancer risk than smoking combustible cigarettes, it is not risk-free. There is currently no conclusive epidemiological evidence establishing a causal link between vaping and cancer incidence in humans. This is largely because cancers typically have long latency periods (decades), and widespread vaping is a relatively recent phenomenon. Therefore, long-term population studies are essential to fully quantify the cancer risk associated with chronic vaping.

E. Other Adverse Effects

Beyond the major organ systems, vaping is associated with several other health concerns and risks:

• Oral Health Problems: Users frequently report dry mouth and throat irritation. Vaping is also linked to gum inflammation (gingivitis) and an increased risk of periodontal (gum) disease. The viscous nature of e-liquids (due to PG/VG) and the presence of sugars in many flavorings can promote bacterial plaque adhesion and potentially increase the risk of dental caries (cavities). Damage to tooth enamel and the development of oral mucosal lesions (sores or abnormal patches in the mouth) have also been reported.
• Immune System Modulation: Emerging research suggests that vaping can impact the immune system. Studies have shown alterations in both innate (first-line defense) and acquired (adaptive) immunity in vapers, including changes in the expression of immune-related genes in nasal passages and increased production of certain inflammatory markers. While the functional consequences are still being investigated, these changes could potentially affect the body’s ability to fight infections.
• Acute Nicotine Poisoning: E-liquids, especially those in high concentrations, pose a significant poisoning risk if ingested, inhaled directly (not aerosolized), or absorbed through the skin or eyes. This is a particular danger for young children who might accidentally access unsecured e-liquids. Symptoms of nicotine poisoning can include nausea, vomiting, dizziness, rapid heart rate, breathing difficulties, and in severe cases, seizures and even death. A large proportion of calls to U.S. poison control centers regarding e-cigarettes involve accidental exposure in children under five years old.
• Device Safety Issues: Beyond the chemical risks, the devices themselves can pose physical hazards. Defective lithium-ion batteries used in many vaping devices have been known to overheat, catch fire, or explode, causing serious burns and other traumatic injuries. These incidents often occur while the device is charging. Additionally, the use of modified or “bootleg” devices and liquids obtained from unregulated sources carries risks of malfunction and exposure to unknown, potentially dangerous substances.

F. Secondhand Aerosol Exposure and Risks

The aerosol exhaled by e-cigarette users, often referred to as secondhand aerosol (SHA), is not simply harmless “water vapor”. The U.S. Surgeon General has concluded that SHA is not harmless. It contains a mixture of potentially harmful substances that can expose bystanders, including children, to risks.

• Composition of Secondhand Aerosol: SHA contains nicotine, ultrafine particles, volatile organic compounds (VOCs) like formaldehyde and benzene, heavy metals (such as lead, nickel, tin, chromium), and various flavoring chemicals. Some of these components, including certain VOCs and metals, are known carcinogens. Propylene glycol, a common e-liquid ingredient also found in SHA, can cause eye, throat, and airway irritation, and long-term inhalation exposure may contribute to asthma development in children.
• Exposure Levels in Indoor Environments: Vaping indoors significantly increases the concentration of airborne particulate matter (PM2.5 and ultrafine particles) compared to background levels. Studies have measured substantial increases in PM2.5 in various indoor settings:

• Rooms: Peak PM2.5 concentrations can reach very high levels immediately after puffing (e.g., ~3 × 10³ µg/m³ near the user), dropping quickly but still elevating overall room levels. Average PM2.5 levels during vaping sessions in rooms have been measured at levels significantly above background (e.g., 21 µg/m³ , 197 µg/m³ ). Vape shops can have particularly high average PM2.5 concentrations (e.g., 276 µg/m³). These levels can exceed WHO 24-hour air quality guidelines (15 µg/m³).
• Cars: Vaping in cars also elevates PM2.5 levels, with measured concentrations ranging from 16 µg/m³ to over 100 µg/m³ during sessions. The small volume of cars can lead to high concentrations.
• Nicotine: Nicotine is consistently detected in the air of indoor environments where vaping occurs, including homes and vape shops. Bystanders exposed to SHA absorb nicotine, as evidenced by biomarkers like cotinine in their bodies. Nicotine also deposits on indoor surfaces, creating potential for thirdhand exposure.
• Health Effects, Especially on Children: Exposure to SHA is associated with adverse health effects, particularly respiratory issues:

• Studies link SHA exposure to increased risk of bronchitic symptoms and shortness of breath in young adults. Bystanders exposed have reported irritation symptoms like dry throat, nose, eyes, and cough.
• For children, SHA exposure poses specific risks. It is associated with an increased likelihood of asthma attacks or exacerbations. One study found youth with asthma exposed to SHA had 27% higher odds of reporting an asthma attack in the past year. Another suggested exposure at home leads to more asthma symptoms, especially in younger children (ages 5-11).
• The nicotine in SHA is a concern for children’s developing brains. While children exposed only to SHA absorb significantly less nicotine than those exposed to secondhand smoke (about 84% lower based on cotinine levels), they still absorb significantly more nicotine than unexposed children.
• Given these risks, health authorities recommend prohibiting vaping in indoor spaces to protect bystanders, especially children.