We used to do this in Tai Chi and I then read that it is good for preventing dementia! Read it in our Sunday paper so is perhaps not true!
Anyway I could do it for minutes when I was doing Tai Chi however now I cannot do it for so long.
I can do it on one side but not on the other which seems to be the way with a lot of things with me even though I am ambi dextrous.
One foot I can do it for a long time but not the other, however as soon as I close my eyes, I lose my balance so obviously you need sight to balance? We were taught at tai chi to focus on something to help with this exercise.