Reiki is a Japanese energy healing practice that supports your body's innate ability to heal itself by stimulating the free-flow of your energy from head to toe. Any thought or emotion that puts your nervous system on high alert can create an energy block like a dam impeding the flow of a river.
Using gentle hand placement on your fully clothed body or hovering palms above you, your Reiki practitioner connects with your energy flow, encouraging its movement and clearing blocks.
This might feel like tingling, coolness or heat, and most commonly, deep relaxation similar to what you'd experience during a massage. Other sensory responses include visualizing colors in your mind's eye or feeling very light as if emotional baggage has been lifted off your shoulders.
While the mechanism of how Reiki works is yet to be determined, its significant effects on quality of life continue to be reported. Reiki has been used to alleviate the side effects of chemotherapy, improve surgical outcomes, provide pain relief, reduce anxiety, and improve sleep quality.
For further reading:
https://www.everydayhealth.com/reiki/