Answer:
that depends on the type and where you get it some ppl lace it and thats def a 10 but some is used for medical reasons and thats probably only like a 2-5 i think smokeing anything can damige your lungs so you have to be carful and only use a little bit also starting at a younge age will f### up your brain (expecially if its a lottt) so really think about it before hand and make the desision you want all in all id say 3-5 out of 10
Explanation:
The Spirometry! It can measure many different ways on how you breathe, like how much air is inhaled and how much air is exhaled.
In soccer your hand muscles don't develop because it gives legs straight
In tennis your foot muscles don't developed cause it's flexing arm strength
Hope this helps:)