Following your nose

From "The Science of Breath" by Swami Rama, Rudolph Ballentine and Alan Hymes (Himalayan Institute Press) page 67.

"...yoga manuals recommend that that one lie on the left side after meals, opening the right nostril and stimulating the digestive process. Traditionally, too, it is said that when individuals go to bed, they should lie on the left side for five or ten minutes, activating the right nostril to create increased body heat. As soon as they are warm and comfortable, they should turn to the right, allowing the left nostril to open. Doing so, relaxes, calms and prepares them for sleep."

But why should this be so? More tomorrow...