Mary Kuhner wrote:
One of my teachers recommends turning off the hot water at the end of a shower and trying to control your breathing through the shock of having cold water spray on you. (This is the "home version" of cold-water misogi.) He says that if you can learn to control your breathing through that, it will carry over into ukemi. You can ki-ai on the exhale to make it easier.
I will admit, I don't do this very often, and usually end up springing out of the shower as if poked by a pin....
My grandfather believed in the cold bath. And he used to chuck me in too! The Result? I like jumping in the cold bath at the bath house. I have also tried to control my breath at that moment.
I also used to go canoeing - even in winter. Wet-suit or not, the first dunk of the day in a freezing river takes control of your body away from you. The shock to your body is so much that you cannot even breathe for a moment, sometimes a few seconds. In fact, your muslces also freeze up and your body can barely move. Once used to it, you are 'in control' of this lack of control. You relax, bob about a little, and slowly get the breathing and moving of limbs in order. And then reach for that damned canoe ...
It's not the shock of falling into a cold river that kills, it is the panic the sudden shock (of being momentarily 'frozen-stiff' if you like) can create. So, I think your cold shower idea has merit. Except, as I remember, Aikikai Hombu only had cold showers. So, I recommend, try it without the hot part and see how that wakes you up for the day