What is happening when we stand up too quickly and our vision goes black and we feel dizzy (head rush) ? – Sports Science Zone

Question: What is happening when we stand up too quickly and our vision goes black and we feel dizzy (head rush) ?
- Keywords:
  brain,
  dizzy,
  head,
  vision
Asked by hazellwh to Helen, Jenni, Mark, Martin, Stu on 17 Jun 2011. This question was also asked by bealeewh.