There is no such thing as what is the best blood pressure for a 40 year old. Usually, a 40 year old’s blood pressure should be in the normal range of 90-120mmHg systolic and 60-80mmHg diastolic. If the blood pressure is too low or too high, there will be uncomfortable symptoms, some people experience dizziness, nausea, insomnia, palpitations (rapid heartbeat, often accompanied by panic) and other symptoms, after middle age, irregular living habits, easy to cause cardiovascular and cerebrovascular diseases. It is recommended to take appropriate physical exercise and avoid exposure to harmful substances such as radiation. Attention should be paid to a low-salt and low-sugar diet, and more fresh vegetables and fruits should be eaten to help improve the immune function. In addition, if the blood pressure value is abnormal for a long time, it is recommended to go to the hospital in time to avoid delaying the condition.