Apparently, after you sprain your wrist, you should rest it and put ice on it, but also, you should keep it above your heart level.

 

http://www.webmd.com/fitness-exercise/wrist-sprain

http://orthoinfo.aaos.org/topic.cfm?topic=a00023

 

I wonder why is that? Possibly to reduce the swelling?

Rest
Ice
Compression
Elevation

Otherwise known as RICE, is how you should care for a sprain for roughly the first 24-48 hours (unless they changed the rules on me again).

Ice, compression and elevation (and to some extent rest) are all aimed at reducing swelling and the potential resultant additional damage to the area sprained.