Going down the stairs burns just a third of the energy needed to climb up the stairs. It requires more energy. While, on the other hand, coming down requires lesser energy because you are working in the direction of the gravity. Gravitational pull of the earth helps you in that. Going up, you are working or pushing yourself in the opposite direction of the force of gravity. Moreover, you have to lift your body weight up the stairs.
Why is ascending stairs more exhausting than descending them?
