The human body has self-protection mechanisms and does not usually experience this feeling of congestion. If you think you are congested in the brain, there are several reasons: 1. Rapid blood pressure rise: For example, blood pressure was originally around 120-130 mmHg, but rose sharply to 170-180 mmHg due to various reasons, this rapid rise in blood pressure will cause brain discomfort. Because the human body’s vascular auto-constriction function will cause disorders, once the blood vessels in this case expand, it will cause a sense of brain expansion and headache in the brain, which is the most important cause of cerebral vascular filling; 2. Other causes: for example, some people will have a fever, and after the fever, the blood flow will speed up and they will feel a sense of head fullness. These are a few of the more common causes, so when you encounter head swelling, you must pay attention to whether your blood pressure is high or not, and if it is, there is an urgent need for intervention and treatment.