Well, here are things I can suggest
1. Go to a massage therapist. They can show you what areas to massage (there is one tendon that extends from the arms to the hand) or rub to get circulation and loose the tendons.
2. Linnetbird is right. Rest also helps. ake a break inbetween typing like taking a break to rest your eyes.
3. Linnetbird is right again. Ergomonic keyboards, mouse will help too.
4. Take up a hobby that requires your hands but not typing. Knitting, origami, clay sculptures, etc.
5. Stretch your hands and arms. Bend your wrists inward to your arm (towards your chest) and hold and then do the reverse (like a prayer but you apply pressure to get the stretch). But not too hard. Rotate your wrist too. Get motion in your hands and wrist other than typing.
6. File for workers comp :)