I’m an ex-smoker, but I’m able to have a couple every month or two without going back full blown. One thing I have noticed is how smoking spikes your heart rate. I can look at my Fitbit data and see exactly where I smoked.

I’d heard about weight gain from quitting, which I have experienced, but I always thought it was attributed to increased appetite and not linked to cardiac activity. The stress on your heart is not just cumulative, it is acutely affective every time you light up.