The most common causes of afternoon dizziness are the following: 1. The most common cause is hypertension, and patients with hypertension have a characteristic that early afternoon dizziness and headache can occur, so it is recommended that blood pressure be measured. If the blood pressure is higher than 140/90mmHg, it is recommended to take medication to treat the condition, and if the blood pressure is low, if the systolic blood pressure is lower than 90mmHg, the phenomenon of dizziness can also occur, and it is necessary to go to the hospital. 2. It is recommended to measure the blood pressure while lying down and again after standing up. If the blood pressure fluctuates too much and exceeds 20 mmHg, postural hypotension can cause dizziness. 4, there are other causes, such as poor sleep, emotional anxiety and depression, which can also trigger the above phenomenon.