Active poses that stimulate the blood flow throughout the body specifically those that gradually stretch the spine can assist in combating fatigue and boost those feelings of strength and energy. It may also help to offset a number of of the effects from long intervals of sitting.
As you stretch your spine, it invigorates the nervous system. This is why the back bends are so revitalizing. In addition, you're bringing more impact to the heart and opening up the chest muscles, when you're moving in the back bending way, which really opens up the body.