Not Enough Oxygen

• People get light-headed when they aren't getting enough oxygen to the brain. The fogginess and faintness that comes with it indicates that your brain doesn't have enough oxygen to stay alert, and is shutting down.
  
  

First Sign of a Health Problem

• Light-headedness often accompanies low blood sugar. It can also be indicative of a stroke or other circulatory problem. People with anemia sometimes report feelings of light-headedness, as do diabetics.
  
  

Overheating

• Overheating drains the body of fluids, dehydrating you. This may cause you to become light-headed. This is usually cured by stepping inside an air-conditioned building and drinking some water.
  
  

Hyperventilation

• Nervousness or breathing too rapidly may result in hyperventilation, which reduces oxygen levels in your body while increasing carbon dioxide. Hold your breath for several seconds---or take slow and deep breaths into a paper bag---until your light-headedness goes away.
  
  

Recurring Light-headedness

• See your doctor if you are experiencing recurring light-headedness; it may be an indication of a serious health problem.