Effects of Nicotine on the Body
Nicotine poses significant risks to the cardiovascular system, including increased blood pressure, heart rate, blood flow to the heart, and arterial narrowing, which can lead to heart attacks and contribute to the hardening of arterial walls. 1
Cardiovascular Effects
Nicotine has profound effects on the cardiovascular system:
- Increases heart rate and myocardial contractility 1, 2
- Elevates blood pressure 1, 2
- Causes narrowing of the arteries 1
- Contributes to arterial wall hardening (atherosclerosis) 1
- Plays a major role in the development of coronary artery disease 1
- May contribute to the development of aortic aneurysms 1
- Creates a detrimental effect on cardiac oxygen balance by simultaneously increasing oxygen demand and coronary resistance 2
- Sensitizes the ischemic heart, potentially triggering acute cardiovascular events like myocardial infarction and life-threatening arrhythmias 2
Neurological Effects
Nicotine significantly impacts the brain and nervous system:
- Highly addictive substance that affects neurotransmitter release 3
- Facilitates release of dopamine, glutamate, and gamma-aminobutyric acid, which are crucial in developing nicotine dependence 3
- Affects neuroregulation and causes structural changes in the brain 1
- Alters neurologic development, particularly concerning in adolescents 1
- May inhibit estrogen signaling in women's brains, potentially making them more susceptible to ischemia 1
Effects During Pregnancy and on Development
Nicotine exposure is particularly harmful during pregnancy and development:
- Crosses the placenta during pregnancy 1
- Associated with multiple adverse consequences including sudden infant death syndrome 1
- In utero exposure linked to impaired fertility, type 2 diabetes, obesity, hypertension, neurobehavioral defects, and respiratory dysfunction later in life 1
- Has genotoxic effects on fetal cells 1
Other Systemic Effects
Nicotine affects multiple other body systems:
- Gastrointestinal: Associated with peptic ulcer development and gastrointestinal cancer 1
- Oncological: May promote tumor angiogenesis 1
- Skeletal: Deleterious effects on bones in both animal models and humans 1
- Respiratory: Structural changes in the lungs that could increase vulnerability to hypoxia 1
Special Considerations
Adolescents
Adolescents are particularly vulnerable to nicotine's effects:
- Nicotine exposure during adolescence can harm the developing brain 1
- Can cause addiction more readily in younger individuals 1
- The CDC reported doubling of e-cigarette use among middle and high school students from 2011 to 2012 1
Patients with Existing Cardiovascular Conditions
The FDA warns that individuals with the following conditions should consult a doctor before using nicotine products 4:
- Heart disease
- Recent heart attack
- Irregular heartbeat
- High blood pressure not controlled with medication
Therapeutic Applications
Despite its harmful effects, nicotine has been investigated for therapeutic uses:
- Smoking cessation through regulated nicotine replacement therapy 4, 3
- Potential applications in ulcerative colitis, Alzheimer's disease, Parkinson's disease, Tourette's syndrome, sleep apnea, and attention deficit disorder 5, 6
Important Caveats
- While nicotine replacement therapy has a good safety record when properly regulated, unregulated nicotine delivery systems (like e-cigarettes) have not been adequately tested, standardized, or regulated, making their safety uncertain 1
- Nicotine addiction is more common in persons with mental illness and substance abuse disorders 3
- Genetic factors influence vulnerability to nicotine dependence and metabolism rates, affecting addiction potential and cancer risk 3
- Even when using nicotine replacement therapy, patients should be monitored for signs of nicotine overdose including nausea, vomiting, dizziness, weakness, and rapid heartbeat 4
The evidence clearly demonstrates that nicotine is far from a benign substance and has widespread effects throughout the body, with particular concerns for cardiovascular health, brain development in youth, and fetal development during pregnancy.