Smoking and cardiovascular disease: risks

What is tobacco dependence, and why does it threaten the heart?

Tobacco dependence is a chronic disease driven by nicotine addiction and one of the leading modifiable cardiovascular risk factors. Guidelines recommend stopping tobacco completely, including for people who already have cardiovascular disease^1,2,3. Brazil’s National Cancer Institute (INCA) estimates that smokers have two to four times the risk of coronary heart disease and stroke compared with nonsmokers; these are population-level relative risks, not a prediction of any individual’s chance of an event². There is also no scientific basis for calling light smoking safe: a meta-analysis of 141 cohort studies found that smoking about one cigarette per day retains a substantial share of the excess coronary heart disease and stroke risk observed with 20 cigarettes per day⁴. The relationship is not simply linear because a relevant share of the harm occurs at low levels of consumption⁴.

How do smoke, nicotine, and carbon monoxide affect the cardiovascular system?

Cigarette smoke simultaneously harms the heart, blood, and arterial walls. Nicotine activates the sympathetic nervous system, acutely raising heart rate and blood pressure, constricting blood vessels, and increasing the heart’s workload and oxygen demand with every episode of use—even if blood pressure appears normal when measured at another time^5,6,7. Carbon monoxide from combustion moves from the lungs into the bloodstream and reduces red blood cells’ ability to carry oxygen precisely when nicotine is making the heart work harder⁵. Oxidants and other toxic substances reduce nitric oxide availability, increase oxidative stress and inflammation, injure the endothelium, and accelerate atherosclerosis⁸. Smoke also activates platelets and clotting and can make plaques more vulnerable to rupture; a heart attack usually occurs when a blood clot suddenly blocks a coronary artery at the site of a disrupted plaque⁸.

Which cardiovascular diseases are linked to smoking?

Smoking causes widespread vascular injury and is associated with angina, myocardial infarction, stroke, peripheral artery disease, aneurysms, and thrombosis^2,8. In disease-burden estimates for 2020, INCA attributed 161,853 deaths in Brazil—about 443 per day—to smoking, including an estimated 33,179 deaths from heart disease and 10,041 from stroke⁹. The same model attributed 444,953 new cases of heart disease and 52,737 strokes to smoking during that year⁹. These figures are epidemiological model estimates for 2020, not a current count of cases or deaths in 2026⁹.

Why is secondhand smoke dangerous?

Secondhand smoke can disrupt the endothelium, platelets, and clotting even in people who have never smoked. The American Heart Association estimates that nonsmokers exposed at home or work have an approximately 25% to 30% higher risk of heart disease⁵. An identifiable meta-analysis published in 2015 associated secondhand smoke exposure with a higher risk of cardiovascular disease and all-cause mortality¹⁰. Even brief exposure may temporarily impair blood vessel and platelet function⁵. Opening windows, using fans, or smoking in another room does not provide adequate protection; effective prevention requires completely smoke-free indoor spaces^5,3.

Are e-cigarettes a safe alternative?

E-cigarette aerosol is not simply water vapor and should not be considered harmless. Depending on the product, it may contain nicotine, propylene glycol, glycerin, flavorings, ultrafine particles, heat-generated compounds, and metals released from the device’s heating element⁶. A small randomized crossover study found acute worsening of peripheral and central hemodynamic measures and arterial stiffness after e-cigarette use⁷. These findings concern short-term effects and surrogate outcomes; they do not prove permanent hypertension in every user or quantify risk after decades of use⁷. The American Heart Association considers acute physiological effects—particularly from nicotine-containing products—well established, but longitudinal studies remain insufficient to determine the precise risks of heart attack, stroke, and death after prolonged exclusive use⁶. In Brazil, Anvisa prohibits the manufacture, importation, sale, distribution, storage, transportation, and advertising of these devices, which should not be treated as a proven safe harm-reduction strategy¹¹.

What happens to the heart after quitting?

Cardiovascular recovery begins after the last cigarette and continues progressively. Within minutes, heart rate starts to fall; within several days, blood carbon monoxide reaches levels similar to those of nonsmokers; within one to two years, heart attack risk drops sharply; within three to six years, excess coronary heart disease risk falls by about half; and by approximately 15 years, that risk approaches the level seen in people who do not smoke¹². Although the largest reductions tend to occur during the early years, the substantial risk retained with low-intensity smoking reinforces that cutting down is not a substitute for quitting completely⁴. Recovery varies with cumulative exposure: observational data indicate that cardiovascular risk declines after cessation but may remain above the risk in never-smokers for years or decades, particularly after greater cumulative exposure¹³. Compared with people who continued smoking, cessation after a heart attack or in established coronary disease was associated with approximate relative reductions of 39% in cardiovascular death, 43% in major cardiovascular events, 36% in nonfatal heart attack, and 30% in nonfatal stroke; these findings came mainly from observational studies, and certainty differed across outcomes¹⁴. Recommended care combines behavioral support with medication when appropriate; Brazil’s Unified Health System (SUS) may provide structured follow-up, nicotine patches or gum, and bupropion after professional assessment^1,15.

When should someone seek care, and how can quitting be planned?

Chest pain or pressure, severe shortness of breath, cold sweats, fainting, or sudden signs of stroke require emergency care; in Brazil, call the Mobile Emergency Care Service (SAMU) at 192¹⁵. Outside Brazil, contact the local emergency service and use the emergency number applicable to that location. When there is no emergency, an individual consultation is recommended to assess nicotine dependence, cumulative exposure, blood pressure, symptoms, associated conditions, and the most suitable treatment—especially after a heart attack, stroke, or arterial disease. Relapses can occur and do not mean permanent failure; the plan can be adjusted with professional support. References:¹ Précoma DB et al. Updated Cardiovascular Prevention Guideline of the Brazilian Society of Cardiology — 2019. Arquivos Brasileiros de Cardiologia. 2019;113(4):787-891. DOI: https://doi.org/10.5935/abc.20190204¹¹ Brazilian Health Regulatory Agency (Anvisa). Anvisa maintains the prohibition of electronic smoking devices. Anvisa, 2024. URL: https://www.gov.br/anvisa/pt-br/assuntos/noticias-anvisa/2024/anvisa-mantem-proibicao-dos-dispositivos-eletronicos-para-fumar² Brazilian National Cancer Institute (INCA). Smoking and cardiovascular diseases. INCA/Brazilian Ministry of Health. URL: https://www.gov.br/inca/pt-br/assuntos/causas-e-prevencao-do-cancer/tabagismo/tabagismo-e-doencas-cardiovasculares⁹ Brazilian National Cancer Institute (INCA). Costs attributable to smoking. National Tobacco Control Policy Observatory, INCA/Brazilian Ministry of Health, 2020 data. URL: https://www.gov.br/inca/pt-br/assuntos/gestor-e-profissional-de-saude/observatorio-da-politica-nacional-de-controle-do-tabaco/dados-e-numeros-do-tabagismo/custos-atribuiveis-ao-tabagismo⁵ American Heart Association. Health Threats from Secondhand Smoke. American Heart Association, 2024. URL: https://www.heart.org/en/healthy-living/healthy-lifestyle/quit-smoking-tobacco/health-risks-of-secondhand-smoke³ U.S. Department of Health and Human Services. The Health Consequences of Involuntary Exposure to Tobacco Smoke: A Report of the Surgeon General. Office of the Surgeon General, 2006. URL: https://www.ncbi.nlm.nih.gov/books/NBK44324/⁸ U.S. Department of Health and Human Services. How Tobacco Smoke Causes Disease: The Biology and Behavioral Basis for Smoking-Attributable Disease. Office of the Surgeon General, 2010. URL: https://www.ncbi.nlm.nih.gov/books/NBK53017/⁴ Hackshaw A, Morris JK, Boniface S, Tang JL, Milenković D. Low cigarette consumption and risk of coronary heart disease and stroke: meta-analysis of 141 cohort studies in 55 study reports. BMJ. 2018;360:j5855. DOI: https://doi.org/10.1136/bmj.j5855¹⁴ Wu AD, Lindson N, Hartmann-Boyce J, et al. Smoking cessation for secondary prevention of cardiovascular disease. Cochrane Database of Systematic Reviews. 2022;8:CD014936. DOI: https://doi.org/10.1002/14651858.CD014936.pub2¹² Centers for Disease Control and Prevention (CDC). Benefits of Quitting Smoking. CDC, 2024. URL: https://www.cdc.gov/tobacco/about/benefits-of-quitting.html¹³ Duncan MS, Freiberg MS, Greevy RA Jr, Kundu S, Vasan RS, Tindle HA. Association of Smoking Cessation With Subsequent Risk of Cardiovascular Disease. JAMA. 2019;322(7):642-650. DOI: https://doi.org/10.1001/jama.2019.10298¹⁰ Lv X, Sun J, Bi Y, et al. Risk of all-cause mortality and cardiovascular disease associated with secondhand smoke exposure: a systematic review and meta-analysis. International Journal of Cardiology. 2015;199:106-115. DOI: https://doi.org/10.1016/j.ijcard.2015.07.011⁶ Wold LE, Tarran R, Crotty Alexander LE, et al. Cardiopulmonary Impact of Electronic Cigarettes and Vaping Products: A Scientific Statement From the American Heart Association. Circulation. 2023;148. DOI: https://doi.org/10.1161/CIR.0000000000001160⁷ Franzen KF et al. E-cigarettes and cigarettes worsen peripheral and central hemodynamics as well as arterial stiffness: a randomized, double-blinded pilot study. Vascular Medicine. 2018;23(5):419-425. DOI: https://doi.org/10.1177/1358863X18779694¹⁵ Brazilian Ministry of Health. Clinical Protocol and Therapeutic Guidelines for Tobacco Dependence. Ministry of Health/Conitec, 2020. URL: https://www.gov.br/conitec/pt-br/midias/protocolos/pcdt_tabagismo.pdf; Brazilian Ministry of Health. SAMU 192 — Mobile Emergency Care Service. URL: https://www.gov.br/saude/pt-br/composicao/saes/samu-192 This content is for information and education only and does not replace an individual medical consultation.