Who's denying you the ability to spin yourself in circles until you "stone" yourself with silliness? Get out of your chair and start spinning--counterclockwise; that way the blood flow will concentrate in the right forebrain...
Ian ---------
Well, just to be tedious, the direction is irrelevant because the problem is blood flow away from the center to the periphery no matter which way you spin. However, we have found `empirically' in the shop the best method is to start a high speed acceleration in one direction, then stop quickly and rotate in the other direction. Nobody gets out of a powerchair standing up after that. Testing proves testing works!
Chuck