Understanding the problem

Smoking causes seven out of every 10 cases of lung cancer, but tobacco is hugely damaging to health in many other, often surprising, ways – from the very first puff.

Immediate effects

Immediately upon inhaling cigarette smoke, instead of oxygen, carbon monoxide binds to haemoglobin in the bloodstream. This means that the body’s cells are starved of the oxygen they require and is part of the reason why smokers get more breathless when they exercise.

It is also why smoking during pregnancy can deprive a baby of oxygen. If a woman smokes while she is pregnant, there is a risk of complications, such as the baby being born below its expected birthweight, or miscarriage.

To compensate for the lack of oxygen, a smoker’s heart rate and blood pressure increase. However, blood flow to the extremities (the hands and the feet) is reduced making the person feel cold. At the same time, the brain and the nervous system are stimulated, which can lead to a jittery feeling.

Smoking also affects the cilia – tiny hair-like structures in the trachea and bronchi – reducing their ability to perform their usual function of moving mucus and other particles up and away from the lungs. This puts the smoker at a higher than usual risk of respiratory infections and can cause a cough to develop as the body tries to clear the chest of unwanted substances in an alternative way. Other immediate effects of smoking include:

• Reduced senses of taste and smell
• A detrimental impact on the complexion
• Yellow staining of the fingers and teeth
• Bad breath.

Long-term effects

Many of the long-term effects of smoking occur in the respiratory system. Cigarette smoke irritates the lining of the breathing tubes (bronchi and bronchioles), which can lead to chronic bronchitis. The symptoms of this typically include shortness of breath, chest pain and a productive cough.

The tar in cigarette smoke can coat the inside of the alveoli, breaking down their structure and reducing the surface area available for gaseous exchange. This can progress to emphysema, which causes sufferers to feel breathless. Emphysema and chronic bronchitis fall under the umbrella term chronic obstructive pulmonary disease (COPD).

Tar – and many of the other chemicals in cigarettes – can cause cancer, not just in the lungs, but in the other parts of the respiratory system such as the throat and mouth. Tar can also affect other parts of the body, such as the kidneys and liver and, as cancer does, it can spread.

Other long-term effects of smoking include:

• Cardiovascular disorders
• Decreased fertility and sexual function
• Gastrointestinal ulcers
• Mental health problems
• Brittle bones (osteoporosis)
• Premature skin ageing.