Dizziness and Vision Darkening When Standing Up from a Squat: Understanding the Causes

Experiencing dizziness and temporary vision darkening when rising from a squatting position is a common phenomenon that may signal an overall reduction in blood flow to the brain. This condition often reflects a temporary insufficiency in cerebral circulation, particularly involving the posterior circulation system, which includes the vertebral and basilar arteries responsible for delivering oxygen-rich blood to critical areas of the brain.

What Causes Dizziness Upon Standing?

Dizziness during position changes is frequently linked to posterior circulation ischemia — a condition where the blood supply to the back of the brain is temporarily reduced. This may occur due to impaired blood flow through the vertebral arteries, which are crucial for maintaining proper brain function, especially during sudden postural changes.

Why Does Vision Darken Temporarily?

Simultaneously experiencing visual darkening is typically due to transient ischemia in both retinal arteries. These arteries branch from the internal carotid arteries and are responsible for supplying blood to the eyes. When blood flow is restricted, even momentarily, it can lead to temporary vision disturbances.

Common Triggers and Risk Factors

This phenomenon often occurs when transitioning from a squatting to standing position because the body must quickly adjust blood flow to maintain adequate brain oxygenation. Several underlying factors may contribute to this issue:

• Orthostatic (postural) hypotension – a sudden drop in blood pressure upon standing
• Low blood volume – caused by dehydration, excessive sweating, diarrhea, or acute blood loss
• Vasovagal response delay – especially common in young women, where the nervous system's regulation of heart rate and blood pressure is momentarily impaired

Diagnostic Considerations

If you frequently experience these symptoms, it's important to undergo proper medical evaluation. Key assessments include:

• Measuring blood pressure in both lying and standing positions to detect orthostatic hypotension
• Conducting blood tests to check for anemia or other conditions affecting blood volume
• Evaluating hydration status and potential causes of fluid loss

While occasional dizziness upon standing is usually not a cause for concern, persistent or severe symptoms should be discussed with a healthcare professional to rule out more serious underlying conditions.