An interesting post on the science of sleep in Indian culture, from the Isha Blog. Reproduced with permission.
In India, you were told that you should not place your head to the north while sleeping. Why? First, let’s look at the way your body is engineered. Your heart is not located half-way down, it is placed three-fourths of the way up because pumping blood up against gravity is more difficult than pumping it down. The blood vessels which go upward are a finer arrangement compared to those going down. As they go up into the brain, they are almost hair-like, to such a point that they cannot even take one extra drop. If one extra drop is pumped in, something will burst and you will have a hemorrhage.
Most people have hemorrhages in their brain. This does not incapacitate you in any major way, but small damages happen. You may become duller, which people are becoming. Your level of intelligence after the age of 35 drops in many ways unless you take enormous care to keep it up. You are managing because of your memory, not because of your intelligence.
When you put your head to the north, what happens? If you have any kind of blood-related problem, let’s say anemia, what would a doctor prescribe? Iron. It is an important ingredient in your blood. You have heard of the magnetic fields on the planet. In many ways, the earth is engineered because of its magnetism. That’s how powerful the magnetic forces are on the planet.
When the body is positioned horizontally, you can immediately make out that your pulse rate drops. The body makes this adjustment because if blood is pumped at the same level, too much will go into your head, causing damage. Now, if you place your head to the north and stay that way for 5 to 6 hours, the magnetic pull will cause pressure on your brain. If you are beyond a certain age and your blood vessels are weak, you could have hemorrhages and paralytic strokes. Or, if your system is sturdy and these things don’t happen to you, you could get up agitated because there is more circulation in the brain than there should be when you are sleeping. It is not that if you do this for one day, you will fall dead. But if you do this every day, you are asking for trouble. What kind of trouble depends on how strong your system is.
So, which is the best direction to sleep with your head pointing towards? East is the best direction. North-east is okay. West is alright. South, if you must. North, no. This is true as long as you are in the northern hemisphere – sleeping with your head towards any side except north is okay. In the southern hemisphere, don’t put your head to the south.
Your heart is an important aspect of your physiology. The station that pumps life across the body – if this one thing doesn’t happen, nothing happens – starts from your left side. In India, the culture has always said that when you wake up, you must roll to your right side and then get out of bed. When your body is in a certain state of relaxation, its metabolic activity is low. When you get up, there is a certain surge of activity. So you need to roll over to your right side and get up because at a lower level of metabolic activity, if you suddenly roll to your left, you will put pressure upon your cardiac system.
In the tradition, they also told you that before you get up in the morning, you must rub your hands together and place your palms upon your eyes. They said that if you do this, you will see God. It is not about seeing God.
There is a heavy concentration of nerve endings in your hands. If you rub your palms together, all the nerve endings are activated and the system comes awake immediately. When you wake up in the morning and still feel sleepy and drowsy, just do this and see, everything comes awake. Instantly, a whole range of nerves connected with your eyes and other aspects of your senses come awake. Before you move your body, your body and brain should be active. You shouldn’t get up dumb, that’s the idea.