When a person faints, they suffer a brief loss of consciousness. It is recommended that you lay the person down and elevate their feet. Most people will recover quickly after fainting once they lay down because more blood can flow to your brain. It also helps to loosen any constrictive clothing.

A person who faints usually will not suffer any long-term health effects. However, it is recommended that you see your doctor after a fainting spell.

What causes fainting?

A drop in blood flow to the brain causes fainting. The most common causes of fainting are usually not signs of a more serious illness. In these cases, you faint because of:

  • The vasovagal reflex, which causes the heart rate to slow and the blood vessels to widen, or dilate. This reflex can be triggered by many things, including stress, pain, fear, coughing, holding your breath, and urinating.
  • Orthostatic hypotension, or a sudden drop in blood pressure when you change position. This can happen if you stand up too fast, get dehydrated, or take certain medicines, such as ones for high blood pressure.

Some people know when they are going to faint because they have symptoms beforehand, such as feeling weak, nauseated, hot, or dizzy. After they wake up, they may feel confused, dizzy, or ill for a while.

What can you do to avoid fainting?

If you know you tend to faint at certain times (such as when you get a shot or have blood drawn), it may help to:

  • Sit with your head between your knees or lie down if you feel faint or have warning signs such as feeling dizzy, weak, warm, or sick to your stomach.
  • Drink plenty of fluids so you don't get dehydrated.
  • Stand up slowly.

When does fainting become more serious?

Fainting may be the sign of a serious problem if:

  • It happens often in a short period.
  • It happens during exercise or a vigorous activity.
  • It happens without warning or if it happens when you are already lying down. (When fainting is not serious, a person often knows it is about to happen and may vomit or feel hot or queasy.)
  • You are losing a lot of blood. This could include internal bleeding that you cannot see.
  • You feel short of breath.
  • You have chest pain.
  • You feel like your heart is racing or beating unevenly (palpitations).
  • It happens along with numbness or tingling on one side of the face or body.