May also be called: Syncope; Swooning; Passing Out More to Know In most cases, fainting — or syncope (SIN-ko-pee) — is not a sign of a dangerous problem. Causes Fainting is a temporary loss of consciousness. It happens when not enough blood reaches the brain due to a fall in blood pressure. Common causes include dehydration, a quick change in position, standing or sitting still for a long period, becoming overheated, hyperventilation (overbreathing), low blood sugar, anemia, sudden fear of something (for example, the sight of blood), and some heart problems. Most cases have warning signs (such as a change in vision, dizziness, nausea, or stomach pain) that happen a few seconds before passing out. Treatment Fainting in children, especially teens, is common but shouldn't be ignored. Discuss it with your doctor, especially if it happens during exertion (exercising, running, etc.) or happens often. Keep in Mind When warning signs of fainting happen, quickly sitting down, dropping the head between the knees, or lying down on the floor may help avoid a loss of consciousness. Then, gradually get up after the dizzy feeling has passed. All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts. Back to Articles Related Articles Fainting Fainting is a temporary loss of consciousness. Someone who has fainted will usually recover quickly. Read More First Aid: Fainting Fainting is a loss of consciousness that can be caused by many things. Here's what to do if your child faints or is about to faint. Read More Breath-Holding Spells Kids who have these spells hold their breath until they pass out. Although upsetting to watch, the spells are not harmful and do not pose any serious, long-term health risks. Read More Fainting Fainting is pretty common in teens. The good news is that most of the time it's not a sign of something serious. Read More Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.