What does it mean when you stand up and stretch everything goes black almost like are momentarily blind feel dizzy so have to hold onto a chair keep your balance?

What happens

As you stand up quickly after lying down, blood in your legs falls to your feet. At the same time, your heart continues to beat at its normal rate, unable to speed up rapidly enough to send the extra blood supply required by your brain. This causes your blood pressure to drop slightly and your blood vessels to narrow.

Blackout

The reduced blood flow to the brain may affect the part of the brain that controls your vision, causing you to momentarily lose your sight. This is known as a 'blackout'.

Dizziness

The change in blood pressure can also cause you to feel dizzy. If the dizziness is severe, you may feel like you're going to faint.

Holding onto something for support

The combination of dizziness and blurred vision can make you feel unsteady on your feet. You may need to hold onto something for support to prevent yourself from falling over.

What to do

If you find that you often feel lightheaded or dizzy when you stand up, it's important to see your doctor. This is especially important if you have other risk factors for heart disease or stroke, such as high blood pressure, high cholesterol, or diabetes.

You can take a number of steps to reduce your risk of dizziness and blackouts, including:

- Drink plenty of fluids before and after standing up.

- Stand up slowly when you move from a lying or sitting position.

- Use a supportive surface like a cane or walker if you need help balancing.

- Avoid standing in one place for long periods, and take breaks to walk around.