I was perusing a totally OT article, when I came across this paragraph:
"Dr. Reinhard Fricke, a retired professor at the University of Muenster in Germany, said his studies showed that people who suffer from rheumatoid arthritis got temporary relief when they were put in chambers as cold as minus 166 degrees for about three minutes because the cold temperature stunted the activity of tissue-destroying enzymes and cells."
That seems a bit extreme, but I definitely feel better in cold than hot.
See the whole article, about spas in Las Vegas, at http://www.cnn.com/2007/TRAVEL/getaways/08/09/vegas.spa.ap/i ndex.html