Why Do You Feel Dizzy and Black Out When Standing Up from a Squat?
Experiencing dizziness, blurred vision, or even fainting when rising from a squatting or seated position is more common than you might think. While it can be alarming, the most likely explanation is a condition known as orthostatic hypotension, also referred to as postural hypotension. This occurs when your blood pressure drops suddenly upon standing, leading to a temporary reduction in blood flow to the brain.
What Happens During Orthostatic Hypotension?
When you're in a squatting or sitting position for an extended period, blood tends to pool in your lower extremities due to gravity. As you stand up quickly, the body may not adjust fast enough to maintain consistent blood pressure. This causes a brief but significant drop in blood supply to the brain, resulting in symptoms like lightheadedness, tunnel vision, or even momentary loss of consciousness.
The heart's ability to pump sufficient blood (cardiac output) may also decrease momentarily during this transition, further contributing to reduced cerebral perfusion. In healthy individuals, the autonomic nervous system usually compensates within seconds by constricting blood vessels and increasing heart rate. However, in some cases, this reflex response is delayed or impaired.
Who Is at Risk?
While occasional episodes are generally harmless, frequent or severe dizziness upon standing should not be ignored. Certain populations are more susceptible, including older adults, those with dehydration, prolonged bed rest, or underlying neurological conditions such as Parkinson's disease. In fact, patients with Parkinsonian syndromes often experience pronounced differences between lying and standing blood pressure, making them particularly prone to falls and syncope after getting up.
How to Prevent Episodes
You can significantly reduce the risk of these dizzy spells by adopting simple lifestyle adjustments:
- Rise slowly: Take a few seconds to transition from squatting or sitting to standing.
- Stay hydrated: Proper fluid intake helps maintain blood volume and pressure.
- Avoid prolonged static positions: Try not to stay in one posture—especially crouching—for too long.
- Engage leg muscles before standing: Flexing your calves and thighs can help push blood back toward the heart.
When to See a Doctor
If you frequently experience dizziness, near-fainting, or actual blackouts when changing positions, it's wise to consult a healthcare provider. A diagnostic test called the supine-to-standing blood pressure test can help identify orthostatic hypotension. During this evaluation, your blood pressure is measured while lying down and then again after standing for 1–3 minutes.
In some cases, medication adjustments or specific treatments may be necessary—especially if an underlying condition like autonomic dysfunction or Parkinson's-related dysautonomia is suspected. Early diagnosis and management can prevent falls, injuries, and improve overall quality of life.
Bottom Line
Feeling dizzy or seeing black spots when standing up isn't always dangerous, but it's your body's way of signaling that something needs attention. By understanding the mechanisms behind orthostatic hypotension and taking preventive steps, you can protect yourself from potential harm. If symptoms persist or worsen, don't hesitate to seek medical advice for a thorough assessment.