First, the Elysium is said to be in the west, so there is often a "death of the west" to describe a person's death; Because of this, the world thinks it is unlucky to sleep with your head facing west, which even means illness and death.
Second, the sun rises in the east and sets in the west, where the sun sets. Therefore, I think it is not appropriate to sleep in this gloomy direction, otherwise it will be harmful to my health and career and go downhill.
Third, the sunshine in the west is the strongest in summer, so the bedrooms and beds in the west are particularly hot, and people inside are easy to get sick because of the high temperature in summer, so the bedside is not suitable for facing west.
However, from the viewpoint of modern science, the earth turns from east to west. If you sleep with your head facing west for a long time, it will cause blood to flow upwards, which will lead to unhealthy health.