Your English is excellent so please don't worry about it.

This is a great article.

I've come across a lot of people who have overcome addictions and one common theme seems to be having a specific reason to do it (other than the health benefits that is).

In your case it was achieving this physical challenge, in other cases it has been due to circumstances beyond their control such as a child developing asthma. I think having another reason beyond just simply giving up helps from a psychological standpoint.

Also aside form the purely psychological there may be some physical/ neurological sense in what you did. Do you think the physical training also helped by replacing a bad habit (smoking) with a good one (running, exercise)? It seems it would replace one form of stimulating your dopaminergic receptors with another - I think there is definitely something to this - it is harder to simply remove one type of stimulation for your brain (e.g. smoking) on it's own than if you substitute another (preferably a healthy one).

I have also seen the reverse when people substitute one bad habit for another (e.g. replacing overeating with smoking - I have had at least 2 female friends who did this and used smoking to lose weight despite the terrible health risks. I think most people would agree that this is not a good thing.)

Anyway sorry to go off on a tangent. This is an inspiring story and hopefully will show others that it can be done. It may even inspire them to try the same method:)