Fun fact:
When breathing, every ml. of air comes in touch with 300cm² of lung surface area.
Now rethink about inhaling that crap.
I don't really know how it affects freediving.
I
guess:
1) Nicotin raises metabolism - bad.
2) Nicotin changes vasoconstriction properties - not sure of to the best or worst.
3) Smoking itself reduces VO2 max - also not sure if it's bad.
4) Reduces Lung tissue flexibility and thuss makes you more prone to lung squeeze at certain depths.
5) High level apnea reduces the body's immune system. Smoking reduces the respiratory immune system. Combine: you're more prone to catching illnesses.
6) Smoking increases mucus production (and an irritable caugh). You might have more problems equalizing.
Anyway, Nicotin is a stupid drug that does nothing to you but makes you dependable on it to feel good because it short circuits the pleasure centers in your brain and makes them work right only with it's presence.
Alison: Caffein is also detrimental to freediving yet when you detox you're doing worse than before (if you really have it bad). A better comparison would be 'breatholding before starting to smoke' and 'breatholding after starting to smoke'. And even then, the more you breathold the more you improve usually, so it's a hard to figure.
Think about it that way: do you think Martin, Mandy, Herbert, Tom, Eric etc. smokes?
EDIT: Forgot, many people say smoking increase CO2 tolerance, which is usually a + unless you can hold your breath till you BO.
EDIT NO.2: Smoking reduces your life expectancy, so it's more probable that you'll have less years to freedive/spearfish in.
