# Seeing Colors

**URL:** <https://boards.straightdope.com/t/seeing-colors/48618>\
**Category:** Factual Questions\
**Created:** [January 5, 2001, 8:48pm UTC](https://boards.straightdope.com/t/seeing-colors/48618 "2001-01-05T20:48:08Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![JCL1013](https://avatars.discourse-cdn.com/v4/letter/j/b9e5f3/32.png) [@JCL1013](https://boards.straightdope.com/u/JCL1013)\
**Post date:** [January 5, 2001, 8:48pm UTC](https://boards.straightdope.com/t/seeing-colors/48618/1 "2001-01-05T20:48:08Z")

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I don’t post very often, but I’m an avid reader. I have see that some of you have quite a bit of medical knowledge. So here’s my question. Sometimes when I stand up I will see splotches of color and sometimes I will also become dizzy. Is there any reason for this that any of you out there have heard of? If you want any additional information I check the boards fairly often. Thank you all for your time.

-Justin

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**Author:** ![Spritle](https://avatars.discourse-cdn.com/v4/letter/s/5daacb/32.png) [@Spritle](https://boards.straightdope.com/u/Spritle)\
**Post date:** [January 5, 2001, 8:52pm UTC](https://boards.straightdope.com/t/seeing-colors/48618/2 "2001-01-05T20:52:45Z")

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When you sit for a while, your heart gets into a rhythm. When you stand up, blood is overcome by gravity and has a tough time going all the way up you your head. Your heart gets a signal that it has to increase the pressure. This takes a second or two to get fresh blood up to your head. During this time, you see spots, etc.

In short, it’s due to a drop in blood pressure.

I learned all this from watching “Hemo the Magnificent”.