Our brain is made up of approximately 100 billion nerve cells (called neurons). Neurons have an amazing ability to collect and transmit electrochemical signals. The only reason a person can evolve from a monkey to a human is that he has the ability to stand on two feet.
why? Because when the brain is at the same level as other parts of the body, a large amount of blood will flow into the brain, causing the brain, nerves and their nerve endings or dendrites to die. These neurons are connected by a neural network, so that a trivial amount of blood will make them ineffective or unusable. But people have learned to walk on two feet, and when they sleep, they use pillows or the like to make their head higher than other parts of the body.
The higher head position allows humans to develop intelligence because neurons are kept in that position. If a pillow is used at one station, it will be very harmful to the brain.
There is no pain in a certain part of the brain, because the brain does not have pain receptors. This is by design. Certain neurons are so small that no amount of blood can get there because they are affected by blood flow. Damaged.
Therefore, a good pillow height is very necessary for good sleep and better brain health. No animal raises its head when the sleep evaluator, some animals can fall asleep while standing and their neck/brain part is lower than the body.