Smoking and your health

Tobacco smoke contains more than 7000 harmful chemicals. These chemicals reach your brain, heart and other organs within 10 seconds of inhaling the smoke.

Health risks

Tobacco smoke contains more than 7000 harmful chemicals; these chemicals reach your brain, heart and other organs within 10 seconds of inhaling the smoke. 

There is no safe level of smoking. Sadly, tobacco smoking kills two thirds of the people who smoke long term. 

If you smoke you are at much higher risk of getting cancer, lung and heart disease. Smoking can also weaken your bones so that they break easily and makes you more likely to develop type 2 diabetes and other serious illnesses. 

Smoking during pregnancy is one of the largest avoidable causes of serious issues in pregnancy.

Nicotine dependence

Tobacco contains nicotine, which is a very addictive drug. When you smoke, you quickly become dependent on nicotine. Many people start smoking when they are teenagers. Teenagers are more susceptible to nicotine addiction. Many people who smoke wish they hadn’t started and find it difficult to quit.

Nicotine and mood are connected. Nicotine changes your brain to make you feel bad when the nicotine levels fall, and this can feel like anxiety.

Having more nicotine makes you feel normal again for a short while before the same thing happens again. This is why some regular smokers wrongly think that nicotine helps them with anxiety. 

Find out what happens in your brain when you smoke in how nicotine works.

Second- hand smoke

Smoking tobacco also harms the people around you. There is no safe level of tobacco smoke exposure. If a non-smoker breathes in your smoke this is called passive smoking.

Passive smoking is especially risky for unborn babies, children and young people, and people with breathing problems. Non-smokers who live with a person who smokes have a 25% to 30% greater risk of developing heart disease.

Third-hand smoke

Third-hand smoke is the coating of chemicals left behind on surfaces, and in dust when someone smokes inside. It is very difficult to remove and may contaminate a place for years. 

Animal studies have demonstrated that thirdhand smoke is likely to be toxic to the liver and lung, reduce wound healing and lead to hyperactive behaviour.

Young children are more at risk of thirdhand smoke exposure if they are carried by a person who smokes. Small children also spend more time in close contact with carpets, blankets, and other contaminated objects.

It’s never too late to quit

From the moment you stop smoking your body begins to repair itself and you will notice the benefits of being smoke free quite quickly. After smoking your last cigarette within: 

  • 20 minutes - your resting heart rate starts to decrease 
  • 12 hours - your blood oxygen levels start to improve and carbon monoxide in your body begins to decrease
  • 5 days – most of the nicotine has left your body
  • 1 week – your sense of taste and smell improves
  • 2 – 12 weeks – your risk of a heart attack starts to reduce, and your circulation starts to improve. Exercise is becoming easier and your lungs function better
  • 1-9 months – you are short of breath less frequently and you cough less
  • 1 year – your risk of having a heart attack has decreased to about half to what it would have been if you had continued smoking. 


Withdrawal can bring about physical and emotional changes, which may include:

  • cravings
  • irritability, frustration, depression and anxiety
  • restlessness
  • difficulty concentrating
  • changed sleeping patterns
  • increase in appetite and weight gain.

Withdrawal symptoms are all signs that the body is recovering and getting used to living without nicotine. On average, most symptoms are gone within two to four weeks, but some people may have some symptoms for a few more weeks. 

Get help to quit

If you’re ready to quit you can find out how to get support at get help to quit

Page last updated on: 21 Jul 2023