If there is one universal constant marker for good health, it must be sleep. Everyone needs a good night sleep, and you know it's so when you don't get it. Especially being awakened by someone else's insomnia, jarred out of a deep sleep, and not being able to find your way back.
A useful imagery I've found is to picture beautiful jelly fish, pulsing and spreading their gossamer tendrils, drifting slowly down into deeper, darker water. Fill your mind with the image, and shut off the chatter, and you can find your way back to the land of nod. Restful, nourishing sleep, helps repair everything.