High sodium may present with symptoms such as thirst, oliguria, increased heart rate, and changes in blood pressure. 1. Thirst and oliguria: the earliest symptoms of elevated serum sodium. 2. Accelerated heart rate: patients with elevated serum sodium, when there is a drop in blood volume, the heart rate will be faster than normal, i.e., heart rate >100 beats/min, or 20% faster than their usual resting heart rate. 3. Blood pressure changes: when blood volume decreases, upright hypotension will occur; when blood volume increases, hypertension will occur. 4. Others: dry skin, decreased elasticity, generalized weakness, decreased work efficiency, lethargy, mental abnormality, answering questions, fainting, epileptic-like seizures, coma, etc. may also occur. When the above symptoms occur, it is recommended to go to the hospital for timely treatment.