Emotional wellness can be improved with meditation, a sense of purpose, and mindfulness. Improved mental health can increase physical health.
Here are some books to start with!
Reinventing medicine: beyond mind-body to a new era of healing by Larry Dossey.
The balance within: the science connecting health and emotions by Esther M. Sternberg.
The cure within: a history of mind-body medicine by Anne Harrington.
Spiritual therapy; how the physician, psychiatrist and minister collaborate in healing by Richard K. Young and Albert L. Meiburg. (258)
Manual of psychomagic: the practice of shamanic psychotherapy by Alejandro Jodorowsky ; translated by Rachael LaValley. (131)