hey there,i used to run when i was a size 10,i started off at 10 minutes walk at 5mph and increase to 7mph 1 min walk,1 min run,2 min walk,2 min run...it really worked wonders! by 5 weeks in i was running 2-4 miles depending on my mood that day and im a smoker too! thats another habit ill be combatting very soon! oh and music that you like really helps too!