Long-term left side sleep has four main hazards: first, the heart has an impact, because the heart is located in the left position of the chest, after long-term left side sleep will lead to the heart in a state of pressure, easy to appear chest tightness, panic or chest pain symptoms. Second, when lying on the left side, the position of the shoulders and upper limbs will be squeezed, resulting in muscle strain, and blood circulation is slowed, prone to inflammation of the left upper limb, pain and unfavorable symptoms of activity. Third, prone to gastritis, mainly due to the left side of the position of the stomach, there will be a lot of gastric acid in the location of the accumulation, which will produce damage to the gastric mucosa; and choose the right side of the position, the stomach can be timely excretion of gastric acid, so the stimulation of the stomach is relatively small. Fourth, the impact on the right hip joint, because in the left lateral position, the right hip joint is in a state of internal rotation, which will lead to the lateral and posterior hip muscles, tendons, ligaments, etc. in a state of strain fatigue, but also easy to appear in this position of muscle strain, pain and unfavorable symptoms of activity.