Many people suffer from Panic Attacks, normally they are brought on by Anxiety, causing sudden Hypervenyilation (over breathing) and profuse sweating. It may feel as if you can't breathe and cause dizzyness and blurred vision and you may feel as if you are about to pass out.

If you see someone like this who looks as if they are going to collapse then do not worry, just support them slowly to lay down and encourage them to breathe slowy, if they do actually pass out then their body will immediately relax and the panic attack will cease.

If this is a regular occurance then seek medical help from your GP.