• Question: Why do you go very dizzy when you stand up really quick?

    Asked by kayleighbarly to Sarah on 24 Jun 2010 in Categories: .
    • Photo: Sarah Burl

      Sarah Burl answered on 24 Jun 2010:

      Because the blood that has settled in our legs when we have been sitting down takes a few seconds to get back up to the head when you stand up The blood prressure is lower when sitting down and then has to increase when we stand up. The blood is pushed upwards against gravity by the heart with the use of valves in the veins. Without these valves the blood would just fall back down to the legs again and we would be in a right state! If you have low blood pressure or bad circulation this happens more often.

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