Whether you call it passing out, fainting or blacking out, being in a state of unconsciousness can be scary and may indicate a wide range of medical problems. In this article, we'll discuss some underlying causes for this medical condition so you'll know if and when to call a doctor after passing out.
Many blackouts result from a sudden, reduced blood flow to the brain. This means less oxygen gets to the brain, causing a person to lose consciousness, or to faint, usually for a few seconds or minutes. Reduced blood flow to the brain can occur when the nervous system reacts inappropriately by changing the body's heart rate and blood flow. Many situations -- physical and emotional -- can trigger this nervous system response that results in fainting. For example, being very upset or afraid can cause one to faint. Body movements that interfere with blood flow to the brain, like coughing or stretching, are other possible causes. Hyperventilating, or breathing too fast, during physical activity or other situations can also cause fainting. A sudden drop in blood sugar (usually resulting from going without food for too long) can also trigger a blackout.
Since there are so many causes of fainting, some of which may be serious health conditions, it's difficult to know when to call a doctor after passing out. If you're concerned about a particular incident, see a doctor for an examination, just to be on the safe side.
This is just a short list of possible reasons for passing out. Remember that its important to listen to your body. If you feel that something is wrong, call a doctor and schedule a physical exam to determine if you have an underlying medical issue, or simply experienced a one-time fainting spell.