The following are some of the reasons for dizziness after running: 1. Patients usually lack physical exercise, and sudden changes in respiratory rhythm after running can cause hyperventilation, resulting in the patient’s brain and body being in a state of hypoxia, making the patient dizzy. 2. 3, dizziness after running may also be related to the increase in blood pressure fluctuations, in the case of exercise intensity is relatively large blood pressure will be affected. Elevated blood pressure will lead to the expansion of blood vessels in the head and increased cerebral blood flow, which will also make patients appear dizzy and swollen.