Kishi researches a lot and then comes up with his stories taking real life events as his inspiration and make it into something much more exagerrated and awesome. Chakra system is a common belief in many hinduism and buddhism cultures. Many chinese healers use chakra in healing techniques. I once saw in Nat Geo about a chinese healer who uses his chakra to heat up his hands to "luke warm water' levels and then use other herbs to heal.
But we cant perform ninjutsu though

... that would be just wacky bro