What Happens To Your Lungs From Smoking? Things You Should Know

Introduction

You’ve probably heard of this disclaimer on multiple occasions – ‘smoking is injurious to health’. What you may not immediately realise is the extent of the damage smoking can cause to your health and, most directly, your lungs.

Smoking is known to be the leading cause of preventable diseases and deaths globally. Nearly all forms of lung cancer, the top cause of cancer death in both men and women, can be attributed to smoking. Tobacco and tobacco-related products can damage the lungs’ ability to supply oxygen to the body. Other substances commonly found in cigarette smoke can cause permanent lung damage, even in small amounts.

How Smoking Changes Your Lungs

A single puff of cigarette smoke contains upwards of 7,000 chemicals. Tobacco smoke contains over 70 known cancer-causing chemicals². When you breathe these in, these toxins go deep into your lungs and can cause swelling, resulting in a host of other respiratory diseases.

Both tobacco and chemical substances found in cigarettes can change the cellular structure of the lungs. They can cause the elastic walls within the airways to break down – resulting in less functioning surface area in the lungs. Cigarettes can damage lung tissue, preventing them from functioning correctly. This can increase the risk of diseases caused by smoking, such as chronic bronchitis, emphysema, respiratory diseases, asthma and COPD (Chronic Obstructive Pulmonary Disease)¹.

Nicotine in tobacco can also damage the ability of the respiratory system to filter out dust and dirt. This can lead to toxic substances passing through, resulting in lung congestion and the ‘smoker’s cough’.

Repercussions of Long-term Smoking

A person who smokes throughout life is at high risk of developing a range of potentially fatal diseases owing to impaired lung function and breathlessness due to swelling and narrowing of the lung airways and excess mucus build-up. They are also prone to weakening the lungs’ clearance system, leading to the accumulation of toxic substances and causing lung irritation and damage. Further, they are also at an increased risk of lung infection, chronic bronchitis and heightened risk of asthma, along with permanent damage to air sacs³.

In the longer term, smoking is known to induce heart disease and stroke, in certain cases, it can cause ulcers of the digestive system and put smokers at increased risk of type 2 diabetes.

Most smokers are also likely to develop emphysema. The number of cigarettes you smoke and other lifestyle factors may impact the extent of the damage. If you’re diagnosed with either of these respiratory diseases – emphysema or chronic bronchitis, you run the risk of being diagnosed with chronic obstructive pulmonary disease (COPD).

Beyond Lung Damage: Diseases Caused by Smoking

Smoking can affect a person’s health in other ways, too, harming almost every organ in the body. In most cases, it can result in a compromised immune system function, making you susceptible to many other illnesses. It can also lead to lower bone density (brittle bones), which increases the risk of broken bones and fractures. Smoking also leaves you at a higher risk of rheumatoid arthritis, heart disease and stroke, along with an increased risk for cataracts (clouding of the eye lenses).

Apart from respiratory diseases, other visible disorders include an increased risk of oral cancers, gum disease and tooth loss, premature ageing of the skin, bad breath and stained teeth and an increased risk for age-related macular degeneration, which can lead to blindness. Moreover, even your wounds may take longer to heal!

How Quitting Can Benefit Your Lungs

It’s never too late to quit smoking. Within days of quitting smoking, lungs begin to repair themselves. In fact, just 12 hours after you quit, the amount of carbon monoxide in your blood drops to a much healthier level. More oxygen flows to your vital organs and you will be able to breathe better. In about 10 to 15 years, your risk of developing lung cancer reduces and may even become the same as a non-smoker⁴.

References

1. Centers for Disease Control and Prevention (US); National Center for Chronic Disease Prevention and Health Promotion (US); Office on Smoking and Health (US). How Tobacco Smoke Causes Disease: The Biology and Behavioral Basis for Smoking-Attributable Disease: A Report of the Surgeon General. Atlanta (GA): Centers for Disease Control and Prevention (US); 2010. 7, Pulmonary Diseases. Available from: https://www.ncbi.nlm.nih.gov/books/NBK53021/

2. National Cancer Institute. Harms of Cigarette Smoking and Health Benefits of Quitting [Internet]. Bethesda (MD): National Cancer Institute; reviewed 19 December 2017 [cited 2025 Sep 19]. Available from: https://www.cancer.gov/about-cancer/causes-prevention/risk/tobacco/cessation-fact-sheet

3. Varghese J, Muntode Gharde P. A Comprehensive Review on the Impacts of Smoking on the Health of an Individual. Cureus. 2023 Oct 5;15(10):e46532. doi: 10.7759/cureus.46532. PMID: 37927763; PMCID: PMC10625450. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC10625450/

4. Centers for Disease Control and Prevention. Benefits of Quitting Smoking [Internet]. Atlanta (GA): CDC; updated May 15, 2024 [cited 2025 Sep 19]. Available from: https://www.cdc.gov/tobacco/about/benefits-of-quitting.html

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