Pillow is too soft and too hard are not good, you should choose a soft and hard moderate, pillow up to let yourself have a comfortable feeling. Pillow if too hard, in the sleep, easy to make the head and neck area of the skin and muscles are compressed, resulting in this part of the blood circulation is not good, long-term, it is easy to headache, neck uncomfortable symptoms. Too soft pillow so that the human neck does not have a sense of force, the head and neck during sleep is easy to present a bad posture, over time it is easy to induce cervical spondylosis. If you have a cervical spine disease, the pillow is too soft, it may make cervical spondylosis aggravated, and in severe cases, it will also induce other diseases. It is recommended that the choice of pillow should be soft and hard, which will help to improve the quality of sleep.