The dictionary says that
vitality means "the power to live or grow" and "the capacity for continuation of a meaningful or purposeful existence." I have always thought of vitality as an exuberance of physical strength and energy, but it is even more intriguing to consider that
the ability to be vital can affect the very nature of our existence.
How is vitality, or life force, freed by the practice of yoga? On a physiological level, yoga liberates energy because it moves fluids. The deep, focused movements of yoga allow muscles to expand and the nervous system to quiet. Breathing, heart rate, and physiological processes slow down so that energy is no longer spent holding tension in the body.
Over time, a wise yoga practice creates more harmonious alignment of bones and muscles, so that less energy is spent holding bones which are misaligned against gravity.
In Katy Bowman's book "Move Your DNA," she proposes that "many of the processes in the body, including genetic expression, can be regulated mechanically," i.e. by how your body carries the load of weight and gravity. She goes on to say that
"your body is literally shaped by your movement experience." So if you sit at a desk with your head forward all day, your tissue will conform to this shape. The excessive shortening and tightening of fascia and other tissue reduces vitality, because it reduces the ability of fluids to move through your body. You literally dry out.
Whenever you are stretching, or moving in unfamiliar ways, you are hydrating, and revitalizing, your body.
Yoga offers a banquet of movements that are outside the box of our everyday, mostly linear and repetitive, movements. Moving this way is like taking a warm bath in re-energizing life force.