The veins on the brain may be related to over-excitement, exercise, high blood pressure and other reasons. 1. Over-excitement: If you are over-excited for some reason, it may lead to an increase in venous pressure, and bruises may appear on your brain. 2. Exercise: When exercising, the perfusion pressure of the body’s tissues and organs is higher, so the venous return will also increase, and bruises may appear on the brain. 3. Hypertension: If you have high blood pressure, the increase of blood pressure will lead to the increase of arterial blood supply and the relative increase of venous return, which will lead to the appearance of blue veins on the brain. As you can see, there are many reasons why there are blue veins on the brain, if they exist all the time or the situation is serious, it is recommended to consult a doctor in time to find out the reasons.