The possible causes are hypertension, heart failure, hyperthyroidism, anemia, anxiety, etc. The details are as follows: 1. Hypertension: Blood pressure should be actively and effectively controlled to keep it in the normal range for a long time. 2. 3, hyperthyroidism: to actively control the excessive secretion of thyroid hormones and maintain the level of thyroid hormones in the normal range. 4, anemia: to effectively improve the anemia, identify the cause of anemia and treat accordingly. 5, anxiety disorders: if necessary, anti-anxiety drugs should be given to control the state of anxiety.