• Question: How come when you stand on your head it starts to heart but when you stand on your feet they don't?

    Asked by tompkinshwh to Helen, Jenni, Mark, Martin, Stu on 24 Jun 2011.
    • Photo: Mark Burnley

      Mark Burnley answered on 21 Jun 2011:

      This is due to differences in blood pressure. In the arteries of the body, blood pressure tends to increase as the blood moves away from the heart if (and only if) you trace the pressure moving downards towards the legs. If you trace pressure towards the head it drops because the blood is having to work against the force of gravity. This is why giraffes need extremely high blood pressure to get the blood to the head when standing upright. If you stand on your head, you reverse the normal situation and blood is accelerated as it moves towards the head, increasing pressure and discomfort.

    • Photo: Helen O'Connor

      Helen O'Connor answered on 24 Jun 2011:

      Hold on, let me go and try both and get back to you!

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