There are many reasons. Tea is obviously one among them. But I'd attribute it to my very easy life so far. Or, I never had to deal with any stress, or may be that I never felt it.

Our culture, our lifestyle, my upbringing, hereditary health, never smoked, drink only sometimes, has an athletic body, play sports and most importantly I take a very healthy vegetarian Indian diet. Indian Vegetarian diet is different from most will call a vegetarian diet.