The Health Effects of Smoking: The Major Ways Smoking Harms Your Health

  • 1st Revision: Sophia Bradshaw
  • 2nd Revision: Tooba Shaker [Linkedin]
  • 3rd Revision: Jasmine Yeh [Linkedin]


Smoking is the act of absorbing air from a product, typically tobacco and tobacco products, into the lung, where it diffuses into the bloodstream. Tobacco can be smoked through cigarettes, cigars, and hookahs. It is now commonly known as a negative health habit. It causes cancer, raises risk of cardiovascular diseases, damages the lungs and leads to diseases such as pulmonary disease and chronic pulmonary obstructive disease, as well as negatively impacting  other diseases (e.g. hypertension). If you are a smoker, it is important for your health to stop smoking. The NHS, as well as many other resources, can help people quit smoking.

The Health Effects Of Smoking

Respiratory Illnesses 

Asthma is an illness in which the airways become narrow and swell. It results in breathing problems, wheezing, and coughing with a whistling sound. Symptoms can range from mild to major depending on disease severity. WHO has a disease handling protocol on diseases, such as upper respiratory diseases and chronic pulmonary obstructive disease, including asthma, that involves lifestyle modeling and smoking cessation.1 Chronic obstructive pulmonary disease (COPD), is characterized by airway blockage and breathing problems. COPD includes emphysema and bronchitis, and can be caused by smoking and secondhand smoke. Exposure to tobacco smoke and bad habits in teenage years can slow down lung growth resulting in an increased risk of getting COPD as an adult. One of the best ways to prevent COPD is to avoid smoking and secondhand smoke, tobacco products, and nicotine from other sources. Secondhand smoke is characterized by breathing air around people who are smoking. According to the CDC, 8 out of 10 COPD-related deaths in the US are caused by smoking.


Cigarette smoking releases harmful chemicals, including carcinogens. It affects all organs and is correlated with at least 15 types of cancer. The number of years a person smokes cigarettes strongly raises the risk of developing cancer. Cigarettes contain 70 carcinogens that can cause irreversible damage to DNA, which can  result in uncontrollable multiplication of cells and abnormal cells, leading to cancer. According to Cancer Research UK, smoking cessation can lead to freedom from 15 types of cancer, including lung and bowel cancer.2

Heart and Cardiovascular Disease

Smoking causes the buildup of plaque in blood vessels. Chemicals in cigarette smoke can thicken blood, causing the formation of clots in veins and arteries. It is one of the primary risk factors associated with cardiovascular health. Moreover, 1 in 10 deaths worldwide due to cardiovascular disease (CVD) in 2000 were shown to be due to smoking. The rapid decline in myocardial infarction risk after smoking cessation shows the effect of smoking on thrombosis. An individual’s risk of coronary heart disease (CHD) also increases if they smoke and have hypertension, diabetes and/or high levels of cholesterol. Smoking quadruples the risk of cardiovascular disease when associated with other risk factors. Moreover, smoking is a major cause of aortic aneurysm, COPD, myocardial infarction, stroke, and CHD. 

The levels of nicotine measured in the body indicate a linear relationship between the number of cigarettes smoked and CVD in many studies. Carbon monoxide in cigarettes causes plaque, oxidation of nitrogen, and free radicals that create oxidant stress resulting in inflammation, platelet activation, and other mechanisms seen in CVD. Lastly, smoking increases heart rate by about 20 beats per minute, which can result in increased myocardial work due to increased myocardial blood flow;this increased blood flow can also cause heart dysfunction.3


Smoking is associated with a 30-40% higher risk of developing Type 2 Diabetes. Cigarette smoking makes the disease unmanageable by making cells more insulin resistant, meaning the cells require more insulin. According to, glycaemic control is lost up to three years after quitting cigarette smoking. This would mean that individuals with diabetes must be more vigilant about their blood glucose levels, even after quitting smoking. Nicotine from smoking and secondhand smoke is responsible for production of more triglycerides that makes the body cells more insulin resistant.4

Increased Risk of Infections

Tobacco use increases the risk of infectious diseases. It creates structural changes in the respiratory tract and decreases immune response of the body. Infectious diseases include pneumococcal disease, tuberculosis, and influenza. Thus, smoking cessation is advised for individuals with susceptibility to these infections. Moreover, secondhand smoke can seriously affect children as well. In a study conducted on children 18 and under, it was shown that 37% of the children were more susceptible to infections as a result of maternal smoking. Viral infections, such as the common cold, influenza, HPV, and HIV, are higher in smokers than in non-smokers. Pneumococcal and influenza vaccine, acyclovir for varicella, and yearly papanicolaou in women are recommended for combating mortality with infectious diseases in smokers.5

Mental Health Issues

Smoking also affects mental health. It causes increased anxiety and stress. It can also cause headaches and migraines. Moreover, nicotine in the cigarette travels through the blood brain barrier and can cause clots, potentially causing strokes and aneurysms. 


Smoking can make it harder to conceive. Individuals - particularly males - who smoke may have a reduced sperm count or abnormal shaped sperm, which can result in an inability of the sperm to reach the egg. Moreover, smoker carry a higher risk of miscarriage and ectopic pregnancies. Smoking cessation can help in improving the lining of the womb.6

Effects of Secondhand Smoking

According to the CDC, secondhand smoke can cause CVDs, sudden infant death syndrome, and cancer. Breathing in secondhand smoke can have immediate adverse effects, such as heart attacks. Secondhand smoking also increases chances of asthma in children, as well as middle ear infections.

Tips for Breaking the Habit

  1. Prepare for ‘quit day’
  2. Go cold turkey and do not smoke at all
  3. Nicotine replacement therapy
  4. Drink more water and juice
  5. Drink no alcohol
  6. Avoid situations that will make you smoke again

For more help with quitting smoking, speak to your GP. There are also many sources available online to help you, including the NHS website

What happens to your body when you stop smoking?

After 20 minutes, the pulse returns to normal. Within 8 hours, oxygen levels will return to normal and nicotine and carbon monoxide levels will decrease by 50%. In 48 hours, there will be an improved sense of taste and smell. After 3 days people may experience irritation, severe headaches, and bad cravings. Lung function improves after 5 months. Lung healing reduces coughing to a lesser extent day by day. 5 years after quitting, the risk of stroke reduces and in 10 years lung cancer risk decreases by 50%. After 20 years the risk of pancreatic cancer reverts back to risk for non-smoker.8

Physical Dependence

If you physically struggle with quitting smoking, you may consider undergoing nicotine replacement therapy (NRT). Nicotine substitutes can be found in many different forms, including nicotine in inhaler or spray form, prescription drugs, e.g., bupropion (Zuban) and varenicline (chantix), OTC gums, patches, and lozenges. Cytisine, a plant derived natural substitute for nicotine, can also be used.9

Psychological Dependence - Replacing the habit with a healthier one

If you struggle psychologically with quitting smoking, you may try replacing the smoking habit with healthier ones. Examples of replacement habits include:

  • Drink a glass of water
  • Eat a dill pickle
  • Have a popsicle or frozen grapes as a healthier snack
  • Gum chewing
  • Creating a ritual for positive habits like laughter, smiling
  • Volunteer and give back to the community
  • Do meditation

To vape or not to vape?

According to, vaping is as damaging to the heart, lungs, and overall health. It is equally addictive and is encouraging more young people to use nicotine products. Thus, it is best to avoid all forms of smoking, cigarette or vapes to protect yourself against unnecessary risks. 


Cigarette smoking is dangerous to health and is capable of damaging all organs in the body. It is dangerous even if done once per day. If you are a smoker, it is strongly advised to quit smoking. There are many channels for help with smoking cessation. Secondhand smoke is equally dangerous, especially to children. 


  1. World Health Organization. Asthma [Internet]. WHO. 2021. Available from:
  2. Cancer Research UK. How does smoking cause cancer? [Internet]. Cancer Research UK. CRUK; 2019. Available from:
  3. Prevention (US) C for DC and, Promotion (US) NC for CDP and H, Health (US) O on S and. How Tobacco Smoke Causes Disease: The Biology and Behavioral Basis for Smoking-Attributable Disease [Internet]. Centers for Disease Control and Prevention (US); 2010 [cited 2022 May 2]. Available from:
  4. How Does Nicotine Affect Blood Sugar? [Internet]. WebMD. Available from:
  5. Scott, D. (2016). Cigarette smoking and bacterial infection. Tobacco Prevention & Cessation, 2(April Supplement).
  6. How smoking affects female and male fertility | Tommy’s [Internet]. Available from:
  7. Nichols H. Five ways to quit smoking [Internet]. 2017. Available from:
  8. A timeline of benefits when you quit smoking | Quit Genius [Internet]. Available from:
  9. WebMD - Better information. Better health. [Internet]. WebMD. 2013 [cited 2022 May 2]. Available from:
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Aarthi Narayan

Master of Science (M.S.), Biological science, University of Illinois Chicago

Scientist with 10+ years of strong industry, academic experience in Molecular biology, Tissue culture, Protein purification techniques. Mid-level experience in Diagnostics and start-ups. Excellent at completing large scale projects and experiments with minimal supervision in a timely and efficient manner.

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