it is true that cigarettes are bad for your health. they will damage your lungs and carry a high risk of inducing cancer. Tobacco is one of the main causes of death in the world.
The figure that you quote may be an average figure – calculated over a large population. But individuals will vary. Some people smoke all their lives and live to be 80. But other smokers might be unlucky enough to get lung cancer in their 30’s or 40s.
So there is no hard rule – just an average.
Of course it’s best not to take any kind of risk with cigarettes – it will always be healthier not to smoke.
If a 20 a day person over 35 years smoking loses 10 years of life (seems reasonable) thats
20x365x35 = about 32,000 ciggies
10x365x24x60x60 seconds =32,000,000seconds
so each cigarette loses you 1000 seconds of life……
Cigarettes are very, very bad for you, and this is not just a preachy thing that people say to scare you. When I found out how bad they were I was completely shocked. I used to smoke as a young adult and I feel like a complete idiot for even thinking about it now.
It can cause lung cancer but also many other serious health problems. It is so sad to see someone close to you dying or suffering serious illness because of this habit. 50% of heavy (25+ per day) smokers will be dead by the age of 70, whereas 80% of non-smokers (never smoked) are still alive. Those it doesn’t kill are very likely to get a range of serious illnesses which will have a substantial impact on your quality of life.
I got these data from the scientific paper that shocked me so much (by Richard Doll and colleagues, in 1994. They followed over 30000 people for 40 years to find out what killed them. I hope you can see the paper by following this link. It is a bit hard to follow, but you can see for yourself how many people (smokers and non-smokers) died from different causes.
I’m very glad that your generation is growing up in a culture where smoking is seen as less acceptable and glamorous than it was when I was a child.