The human body loses heat in three areas: the groin, the armpits and the head. Submerging all three (in Chicago, the head must be dunked for the plunge to be official) can cause hypothermia, leaving the victim drowsy, confused and uncoordinated. It also leads to a massive spike in blood pressure.

Julie Deardorff, Chicago Tribune, Jan. 2, 2005

This was my second time doing the North Avenue Beach polar bear swim. I don't remember there being ice in 2004. To get to the water this year we had to walk gingerly across four feet of jagged, icy shoreline. It was, ho ho, the polar opposite of walking barefoot across hot coals.

Sandy agreed to be my caddy, and it's a good thing he did. Coming out of the water I was disoriented and couldn't find where I'd left my things. I was frantic. But just when I thought my feet had become solid blocks of ice and I'd never tap-dance again, I saw Sandy waving my towel, like a battle flag rising out of the fog of war.

Drowsy? Check. Confused? Check. Uncoordinated? Check. But that's how I spend the first few hours of most days, so I don't know if the water is entirely to blame.