The reasons why blood pressure is higher at night than during the day include poor sleep, irrational medication, sleep apnea syndrome and so on. 1. Sleep apnea syndrome: this part of patients who snore at night are lacking in oxygen at night, and after the lack of oxygen, the body is in a state of stress, and all organs can not get a good rest, and the sympathetic nerves are continuously excited, which will stimulate the rise of blood pressure. 2. Poor sleep: poor sleep at night, such as insomnia, difficulty in falling asleep or sleepy, this part of the people are prone to night blood pressure is higher than the daytime situation. Especially the elderly, or hypertensive diabetic patients, renal function will gradually become worse, the concentration ability of renal tubules is poor, more urine at night, resulting in higher blood pressure at night. 3. Unreasonable medication: For example, if patients with high blood pressure use short-acting antihypertensive drugs, the duration of drug action is shorter, and they lose the effect of the drug at night, which may also lead to an increase in blood pressure. Patients with poorly controlled blood pressure need to seek timely medical treatment and systematic treatment under the guidance of a doctor.