The reasons for sudden dizziness when squatting are the following: 1, due to postural hypotension, people suddenly stand up from squatting because the blood can not quickly supply the brain, which will make the brain ischemia, hypoxia will lead to dizziness. This situation often occurs in hot weather and weakness of the patient, and can be effectively relieved by slowly standing up or holding some kind of object when getting up. 2, the cause of sudden dizziness when squatting may also be the performance of vertigo, and some vertigo belongs to positional vertigo. This situation is actually caused by cervical spondylosis and other diseases, so you should go to the hospital for examination and symptomatic treatment in time.