When I have been sitting down a while, why is it when I get up quickly, I feel dizzy?

Dear Tyler,

While people love that dizzy feeling they get after spinning around on Carnival rides, it can be a little scary when it happens at other times. The dizziness you feel when you stand up quickly is caused bya decrease in blood flow to the brain. Inside your body you have several major arteries—the biggest one is called the aorta. When you are sitting down, the aorta and the arteries in your legs are bent in various positions. When you stand up, those major vessels become straight, kind of like a garden hose, and gravity takes a lot of blood towards your toes. Normally the body responds by pushing the blood through the circulatory system with more force (greater pressure) to overcome the effects of gravity. But if all factors that govern blood pressure are not "in sync" (and you've been sitting for a long while), the increase in blood pressure will not be fast enough and you will feel dizzy.

Feeling dizzy is the body's way of telling you to stop for a moment until the flow of blood to the brain can catch up with the sudden change in position. If there is too much delay in getting blood to your brain, you also could experience blurred vision, fuzzy thinking, weakness and even an upset stomach. These symptoms tell you to sit back down (or lie down) so that more blood can flow to the brain. If you don't heed these symptoms, your body could force you to faint, making you lie down whether you want to or not! In the future, I would recommend getting up slower—unless you just miss that feeling of being on a carnival ride.

---

Copyright © 2014 Apologetics Press, Inc. All rights reserved.

*Please keep in mind that Discovery articles are written for 3rd-6th graders.

This document may be copied, on the condition that it will not be republished in print unless otherwise stated below, and will not be used for any commercial purpose, as long as the following stipulations are observed: (1) Apologetics Press must be designated as the original publisher; (2) the specific Apologetics Press Web site URL must be noted; (3) any references, footnotes, or endnotes that accompany the article must be included with any written reproduction of the article; (4) textual alterations of any kind are strictly forbidden; (5) Some illustrations (e.g., photographs, charts, graphics, etc.) are not the intellectual property of Apologetics Press and as such cannot be reproduced from our site without consent from the person or organization that maintains those intellectual rights; (6) serialization of written material (e.g., running an article in several parts) is permitted, as long as the whole of the material is made available, without editing, in a reasonable length of time; (7) articles, in whole or in part, may not be offered for sale or included in items offered for sale; and (8) articles may be reproduced in electronic form for posting on Web sites pending they are not edited or altered from their original written content and that credit is given to Apologetics Press, including the web location from which the articles were taken. Further, documents may not be copied without source statements (title, author, journal title), and the address of the publisher and owner of rights, as listed below.

For catalog, samples, or further information, contact:

Apologetics Press
230 Landmark Drive
Montgomery, Alabama 36117
U.S.A.
Phone (334) 272-8558

http://www.apologeticspress.org