Prana means life-force in sanskrit and is an integral element of eastern medical arts like Ayurveda, Tibetan medicine, acupuncture, reiki, pranic healing as well as martial arts. It is known as Chi in Chinese and Ki in Japanese.
Every sentient being possess a certain amount of prana, and low prana levels are supposed to correspond with poor physiological and psychological health.
High levels of prana is associated with good physiological and psychological health, faster healing, youthfulness and being mindful or aware without much effort.
Eastern religious and medical philosophies thus focus on increasing and stabilising prana for human betterment and well-being.
Here is an insightful article by Sri Sri Ravi Shankar on the nature of prana, and ways to increase it.
https://www.artofliving.org/wisdom/knowledge-sheets/yagna