chooses and they'd work just the same, as long as you do the simple physical techniques that create de-stressing biochemistry in your body.
I used to teach lessons on meditation, yoga, and chanting as part of my psychology curriculum on consciousness, which included, btw, normal waking conscious, and dreaming.
Yoga and meditation and chanting are biological practices that would work the same way if an individual simply chose to visualize a happy memory, or something they enjoy doing. Breathing deeply isn't magic it's biochemistry. If you want to add chanting, a short piece of poetry, or a bit of song lyrics, or a brief prayer, or an affirmation, or even just 1, 2, 3, 4 - will work, because it's a biological technique that synchs up breathing with positive or at least neural thoughts maintained for sustained periods, to prevent worry or anger or fear and all of their negative effects upon your body. To wind all of those anxiety related biological activities down and eventually to free people from the grip of emotions that are hurting them.
It can be religious, ANY religion, if an individual chooses that, or it can use just about anything else that is pleasant as long as the basic biological techniques are followed.