Imagine your body as a bustling city, smoking cigarette with its 3,000 chemical components will be just like a fleet of bombers setting off to carpet bomb it - with your permission. Smoking harms nearly every organs in the body, and while the theory of each cigarette reducing 11.5 minutes of your life may not be completely true (some smokers live up to their 90s), it's almost certain that in near future you will be spending over 85% of your pension fund undoing smoking damages. Now did you just mention about happy retirement?

Let's start the journey from head to feet; in the head smoking speeds up brain decline, five times faster than non-smokers. Carbon monoxide deprives your brain of oxygen - this blurred a person's ability to accurately judge their actions in long term. Next would be mouth or throat cancer, which 90% of sufferers are smokers; just think of having persistent sore throat, nose inflammation, swollen lymph glands in the neck, sticky phlegm coughs, total loss of voice, or traces of blood in saliva. Life would be dreadful isn't it?

The greatest visible impact will be on your teeth. Tar is responsible for staining your teeth, yellowing it to an unpleasant extent, and this can only be removed with professional dental cleaning. In the meantime, smoking also weakens your gums and caused bad breath. Your non-smoker friends and work colleagues may look at you as someone who doesn't have tooth brushing habit.

Widely documented as the most harmful smoking effects, the lungs absorbed almost everything from a cigarette. Every time you smoke, a portion of air sacks in your lungs (Alveoli) is killed. They won't grow back, which means you have permanently destroyed part of your lungs. The little hair-like structures that help sweep particles out of your lungs (Cilia) are also paralyzed by smoke. Now that the lungs auto-cleaning mechanisms are gone, tar from the cigarette can safely be coated throughout your lungs, blacken it, and eventually causes cancer.

The heart too, is not immune to the effects of smoking. Carbon monoxide in the cigarette smoke increases the amount of cholesterol and constricts blood vessels. This is harmful as it clogs up heart arteries and may lead to heart failure one day. Your heart will now need to work extra hard to pump the same amount of blood as it used to in the past. The thousands of chemicals you smoke in will now dissolve into the blood and be pumped by the heart to everywhere in the body, with consequences that will be detailed below.

Human biology is quite simple, all organs in the body need oxygen, and they are dependent on the heart to pump oxygenated blood for them. But when the heart pumps blood with something else in it, things won't just go normal. The skin, as the largest organ, will be the first to be affected. Poor blood circulation and a partial loss of oxygen will cause premature aging and wrinkles to form; you will look more aged than your actual age.

Reduced oxygen supply also weakens bones, joints and muscles, hence increased chances of fractures and tissue injuries. When tar finally reaches your kidney and colon, it doesn't get flushed out as waste, instead depositing itself there. This is disastrous as you cannot clean them out like how you clean dirt off your car, and it will eventually grow cancerous.

Having learnt so many harmful smoking effects, one of the questions most smokers may ask "With so much damage already done, what's the use I quit now?" Well don't give up, your inner biology returns to its normal state in just 3 months after quitting, and your risk of cancer will resume to nearly the same level as people who have never smoked after several years - so it isn't really too late. Quit smoking now, your body has tried its best everyday to puff out all those harmful chemicals you installed onto it, why ruin its efforts?