I've been dealing with soreness in my wrists for 10 years. Using an ergnomoic keyboard and avoiding the mouse (or mousing lefty when my right hand gets tired) has helped a ton. When it doesn't the wrist exercises I found on Zed Shaw's blog are usually enough to fix it. This week has been particularly bad though and I was thinking about going back to wearing wrist braces, until I found relief in the gym.
I've been foam rolling my legs for a few months to increase flexibility. The foam roller is a PVC pipe wrapped in foam. You lie down, resting the muscle you want to target on the roller and just kind of sway back and forth on it until you find tension. Rolling along that tension helps break it up and restores flexibility to the nearby joints.
In this case my wrist joint was being pulled on by my triceps being tense. I knew rolling any part of my thigh would hit my knee pain, but this was the first time I felt a muscle hurting two joints away (my elbows feel fine FTR). The relief was almost instantaneous, although I've had to keep rolling to keep the pain off. If my description didn't make sense, basically I'm suggesting doing this.
No, this isn't really about code. But it's about being a coder. If I'm going to continue typing for 8 hours a day for the next 30-40 years, my wrists need to keep functioning.