Hello Mark,

I don't think you can read much into this with respect to diving. The experiment was conducted dry. The centralisation of blood volume that is achieved with the head down position in a dry subject is already achieved by peripheral vasoconstriction and loss of gravitational effect in an immersed subject, no matter what position they are in - head up, head down, sideways etc. This is not to detract from the importance of their findings for dry subjects about to escape from a submarine, about to embark on a space walk or in a couple of other contexts I can think of. However, there is probably no relevance to divers.

Warm regards,

Simon Mitchell