It has been said that the tridosha theory in Ayurveda originated from the theory of the three elements of the universe. The names of these three doshas, which are roughly equivalent to humour, are vata (wind), pitta (bile), and Kapha (phlegm), corresponding to the three elements of the universe: air, fire, and water.
Whatever dosha (or doshas) are the most prominent within you will determine
your general tendencies over the course of your life, and what to expect when
you are balanced. This does not change over your life but can manifest slightly
differently in different times of life.
Vata Pitta or Kapha imbalance need not be a fixed thing in one’s life