The Long-Term Effects Of Smoking: Can Quitting Reverse Them?

A burning tobacco cigarette releases smoke that’s filled with hundreds of toxic chemicals. When cigarette smoke is inhaled, it can lead to poor health and contribute to several health conditions. Keep reading to learn about the long-term effects of smoking and how quitting smoking can reverse many of these damaging effects.

What is smoking?

Conventional cigarettes are composed of rolled cigarette paper, shredded tobacco, and a filter. The tobacco plant contains over 2,000 chemicals including nicotine, a highly addictive substance. A lit cigarette releases thousands of chemicals, hundreds of which are toxic. When smoke from a lit cigarette is inhaled, these harmful chemicals enter the lungs and bloodstream, and can lead to unwanted health effects such as heart disease, cancers, and stroke. (17)

Did you know? Vaping refers to inhaling and exhaling an aerosol produced by an electronic cigarette that heats a liquid into vapour without burning or creating smoke. The vaping liquid and aerosol contain dozens of chemicals like glycerol, propylene glycol, and nicotine. (19) Although vaping may be helpful to some for quitting cigarette smoking, the long-term health effects of vaping are unknown. In teens, vaping may alter brain development, affect memory, and lead to addiction. (18)

What is secondhand smoke? 

Secondhand smoke is smoke that’s emitted from the burning end of a cigarette or smoke that’s exhaled by somebody who is smoking a cigarette. Secondhand smoke contains hundreds of toxic chemicals, and can lead to the same unwanted health effects as smoking. (28) 

Did you know? Non-hispanic black Americans, children between the ages of 3 to 11, individuals who live in multi-unit housing, and individuals who work in the service or construction industry are more likely than other groups to be exposed to secondhand smoke. (29)

What makes smoking addictive? 

Nicotine is a chemical in tobacco that causes a psychoactive effect (chemical changes) in the brain that leads to an addiction similar in strength to heroin or cocaine. Nicotine is considered a reinforcing drug, which means that it’s often desired by users despite its dangerous effects, making it especially difficult to quit. (9) 
A small study examined the brains of 22 people who smoked and 21 people who never smoked using high-resolution magnetic resonance imaging (MRI) scans. They determined that the brains of smokers were structurally different from the participants who had never smoked before. The smoking group had more cortical thinning in the left medial orbitofrontal cortex relative to the never-smoking group. These results may signify dysfunctions of the brain in areas involved with impulse control, reward, and decision making in the smoking group. (24)

What are the long-term effects of smoking?

When individuals smoke cigarettes or inhale secondhand smoke, they’re exposed to hundreds of toxic chemicals, including:

• Benzene
• Carbon monoxide
• Formaldehyde
• Hydrogen cyanide
• Tar (17)

Smoking may contribute to over 24 diseases and conditions, reduce health status, and increase the risk of preventable death at any age. (14) It has been associated with the development of cancer in several areas of the body, cardiovascular illnesses such as stroke and heart disease, and lung and respiratory diseases such as chronic obstructive pulmonary disease (COPD), (30) which is an inflammatory condition that obstructs airflow from the lungs. (4) 

Exposure to secondhand smoke is dangerous to people of all ages. In children, it can lead to ear infections, respiratory symptoms such as coughing and wheezing, bronchitis, pneumonia, and more severe asthma symptoms for children with the condition. Secondhand smoke may also interfere with the regulation of a baby’s breathing, making them at increased risk of sudden infant death syndrome (SIDS). (28)

1. Chronic obstructive pulmonary disease (COPD)

The long-term effects of smoking on the lungs are damaging. Smoking is a leading cause of COPD, a respiratory condition characterized by chronic bronchitis (inflammation of the air passageways in the lungs) and emphysema (degeneration of lung tissue). Chemicals in tobacco irritate bronchial tubes which let air in and out of the lungs, and kill the hair-like structures inside bronchial tubes called cilia. Cilia are important for clearing the mucus from the lungs. The risk of dying from COPD (e.g., from heart failure) increases based on the number of years an individual smokes and the number of cigarettes they smoke per day. (11)

Individuals with COPD may utilize drugs, surgery, or oxygen therapy to support the reduction of their COPD symptoms. Quitting smoking also reduces the dangerous health ramifications of COPD. (11) 

One study examined the effectiveness of smoking cessation in smoking patients with COPD and nocturnal oxygen desaturation. Nocturnal oxygen desaturation occurs when blood oxygen levels drop below regular levels during sleep and is a common symptom of COPD. Of the 145 patients included in the study, 51% of them successfully quit smoking with the assistance of counselling, and varenicline, a smoking cessation medication. Pulmonary function parameters were notably improved compared to patients who were unsuccessful in quitting smoking, suggesting an association between improved lung function for individuals with COPD and nocturnal oxygen desaturation, and smoking cessation. (27) 

2. Coronary heart disease 

Toxic chemicals emitted from burning tobacco cigarettes contribute to atherosclerosis (hardening of the arteries) and heart attack risk. Cardiovascular disease refers to several different conditions affecting the heart and blood vessels that can lead to atherosclerosis, such as coronary heart disease (CHD). CHD can lead to angina (chest pain), shortness of breath, and heart attack which occurs when heart blood vessels are being blocked or have narrowed, preventing proper blood flow to the heart. (15) 

Quitting reduces the risk of dangerous cardiovascular-related health effects of smoking. After one year without smoking, research suggests that individuals may reduce their risk of developing CHD by half, and after 15 years, their risk of developing CHD may be comparable to individuals who have never smoked. (15)

A 20-year study that examined the risk of CHD in 6,547 women with type 2 diabetes who smoked regularly determined that cigarette smoking was strongly associated with an increased risk of CHD in this population and that quitting smoking significantly decreased these risks. (1) 

3. Stroke 

Toxic chemicals released from inhaling smoke from burning cigarettes can contribute to atherosclerosis, inflammation of the artery walls, and blood clots (leading to a stroke). (13) A stroke occurs when a blood vessel in the brain is being blocked or an artery in the brain bursts, interrupting blood flow, resulting in brain injury. When the brain is starved of oxygen, it can cause loss of speech and sight and varying levels of paralysis. The risk of stroke has been shown to decrease by over 90% within two to five years after quitting smoking. (6)(34) 

A 2019 meta-analysis that included 14 studies and 303,134 participants examined the relationship between smoking and stroke. The study found not only an increased risk of stroke for smokers compared with nonsmokers but that the risk was dose-dependent. In other words, the risk of stroke increased by 12% with every “five cigarettes per day” increment. In addition, they observed a 45% increase in overall risk of stroke in those exposed to second-hand smoke (passive smoking). There was no association between individuals who used to smoke and stroke, suggesting that quitting smoking had a positive effect on the frequency of stroke. (26)

4. Cancer

Smoking and exposure to secondhand smoke can contribute to the development of cancer in several areas of the body. (30) Chemicals found in tobacco smoke cause genetic changes in cells that can lead to the development of cancer. (12) 

Did you know? The risk of developing lung cancer increases significantly based on the amount of cigarettes smoked per day, the levels of exposure to tobacco smoke, and the number of years an individual smokes. (12) 

A 30-year study that included over 422,000 participants determined that smoking was positively associated with many different types of cancer including liver, bladder, pancreas, kidney, lung, larynx, middle ear, nasal cavity, sinus, pharynx, oral cavity, lip, and lymphatic system. Smoking was not significantly associated with skin, multiple myeloma, endometrial carcinoma, breast, and prostate cancers. (22)

5. Impotence 

Smoking can affect hormones and lead to impotence in men. Impotence, also known as erectile dysfunction (ED), refers to the inability for a man to maintain an erection. (10) Toxic chemicals found in tobacco cigarettes can affect communication between the nervous system, the endocrine system (hormones), and the vascular system that pumps blood into muscle tissue in order to continue an erection, leading to impotence. Depending on the severity of damage that has been caused by smoking, men may be able to regain complete function following quitting smoking. (10)

A 2015 systematic review determined that smoking was significantly associated with erectile dysfunction. (35)  Erectile function requires nitric oxide (NO) production by penile endothelium. Endothelial cells line the inside of blood vessels and have several functions including producing nitric oxide (NO), a gas that helps dilate blood vessels to encourage blood flow. (2) Endothelial dysfunction is one mechanism that may lead to ED in men who smoke. Lastly, exposure to passive secondhand cigarette smoke can also negatively impact erectile function. (35)

6. Pregnancy complications

Smoking during pregnancy is dangerous to those who are pregnant and the developing baby. It can increase the risk of complications such as low birth weights, stillbirths, early births, placental abruption, sudden infant death syndrome (SIDS), and spontaneous abortion. (8) During pregnancy, nicotine and other chemicals are passed to the baby through the placenta, an organ that develops during pregnancy and passes nutrients to the baby from the pregnant person. Quitting smoking during pregnancy is beneficial for the health of both the developing baby and pregnant person and reduces the risk of health problems for the child. (8)

A study that examined the effect of different intensities of smoking cigarettes on the birth weight of newborns demonstrated that in full-term babies, birth weight decreased as the number of cigarettes that were smoked per day increased, indicating a dose-dependent relationship. (23)

7. Female reproductive system concerns

Toxic chemicals from smoking may negatively affect the female reproductive system, increasing the risk of:

• Cervical cancer
• Fertility problems
• Having a baby with a low birth weight 
• Menstrual problems
• Premature delivery (16)

Benefits of quitting smoking over time

Since nicotine is an addictive substance, it can be challenging for individuals to stop smoking. However, the short and long-term benefits of quitting smoking are significant, and quitting improves health status of those who smoke and who are exposed to secondhand smoke. The following effects of quitting smoking are examples of how smoking cessation can offer immediate benefits and significant benefits over time. (7)(20)

Did you know? After quitting smoking, your sense of smell may return to normal and food begins to taste better. (7)

Smoking withdrawal

It’s not uncommon for smokers to have difficulty quitting smoking, especially the first time. Smokers become physically dependent on smoking (nicotine addiction) and withdrawal symptoms can be difficult to overcome. Withdrawal symptoms are more severe during the first week and months of quitting (for some, it can be longer), during periods of stress, and may include:

• Cravings for nicotine
• Decreased heart rate and blood pressure
• Difficulty concentrating 
• Difficulty sleeping
• Hunger
• Headaches
• Irritability and anxiety (9)  

8 tips for quitting smoking

Individuals who choose to quit smoking may find it helpful to create a plan for quitting. The Centers for Disease Control and Prevention (CDC) have highlighted the following eight strategies for quitting smoking.

1. Pick a quit date

It’s helpful to pick a specific quit date that is convenient for you. Ensure that you have no other major commitments on that day so that you will be available to focus on quitting. Circle the date on a calendar as a reminder and to provide you with enough time to prepare and plan ahead. (3)

2. Let loved ones know you are quitting

It’s important to have support from family, friends, and loved ones during the quitting process. Let these people know that you plan to quit, when your quit date is, and how they can help you. (3) For example, you may choose to ask a friend or family member to be your point of contact if you need support during the quitting process.

3. Remove reminders of smoking

Removing reminders of smoking, such as ashtrays, cigarettes, lighters, and matches from your home, office, and car, can help you stick to a quit plan. Cleaning your home and work spaces in order to remove the smell of smoke, which can trigger a craving for some, can also be helpful . (3)

4. Identify your reasons to quit smoking

Create a list of the personal reasons that are motivating you to quit smoking. For example, you may want to become healthier or save money. Keep your list in a place where you can easily see it every day, so you can be reminded regularly of your reasons for quitting. (3) Using a quit cost calculator can be encouraging and remind individuals of how much money they can save by quitting smoking. (21)

5. Identify your smoking triggers

Certain people, smells, activities, and feelings can remind you of smoking. Create a list of triggers that make you feel like you want to smoke, and for each trigger, consider how you will work to avoid them. Similar to your list of motivations, it’s helpful to keep this list close by. (3)

6. Develop coping strategies

During the quitting process, particularly in the beginning, withdrawal symptoms can make it feel more difficult to stick to a quit plan. Coping strategies may be helpful and can include medications, nicotine replacements (e.g., gum, patch, nasal spray), meditation, and counseling.  (3)(5)

A study examined the effect of meditation on the reduction of smoking in regular smokers. Participants were randomly assigned to either a meditation or relaxation group. After two weeks of meditation, smoking was reduced by 60% in the meditation group. No reduction in smoking was observed in the relaxation control group. In the meditation group, areas of the brain related to self-control had increased activity based on brain scan results. These results suggest that meditation may reduce smoking and improve self-control. (32)  

7. Identify resources for immediate help

During the quitting process and withdrawal period, it’s helpful to utilize support systems in your immediate social network and community. This could be a support group, family member, or close friend. You may also consider some of the following resources: 

• Quit smoking apps such as Break it Off and quitGuide
• Quit phone lines in the US and Canada
• Quit text message services

A study that examined the outcomes of smoking abstinence in 478 individuals with COPD over one year determined that a smoking cessation program may be beneficial for staying smoke-free over time. (31) The participants were split into two groups: the smoking cessation program group (the intervention group) and the group who received usual care (control group). The intervention group received two weeks of hospitalization, educational group sessions, phone check-ins for a full year, and nicotine replacement therapy. Physical exercise was also encouraged. After one year, 52% of participants in the intervention group were smoke free compared to 7% of participants in the control group. After three years, 38% of intervention group participants were smoke free compared to 10% in the control group. Quitting smoking is essential to preventing COPD from progressing (33) and smokers with COPD may benefit from additional support during the quitting process in order to remain smoke free long term. (31)  

8. Set up rewards for quit milestones

Reward yourself each time you reach a particular milestone, such as one day, one week, one month without smoking, and so on. Rewards could include going to the movies with a friend, going out for a nice meal, or another enjoyable activity that doesn’t involve smoking.  

The bottom line

Smoking cigarettes and inhaling secondhand smoke can lead to negative health outcomes that affect the lungs, heart, cause cancer, infertility, impotence, and other negative outcomes. When an individual quits smoking, their health improves quickly, and more significantly over time. By remaining smoke free, it’s possible to reverse many of the negative health effects of smoking and decrease the risk of disease development caused by smoking. Smoking is addictive, and quitting smoking can be challenging as a result. The support of a counselor, specific coping strategies, and having people and places to turn to for immediate help are some of the tips that may help a smoking person be successful with the quitting process.