1. - I don´t know anyone ever suffered from RSI, because the most people that I know don´t use the computer, or use it a little time. About the SAD, I live in Andalucia, and we have normally many sunny days in winter, everything opposite, normally we need to use sunglasses many days in winter.
2.- I don´t have any pains, because I have a good chair at my desk, I can adjust its height and its back for sit down correctly and I have many breaks when I´m using my computer, because I can´t be sat a lot of time.
3. -The chair and the keyboard should have the correct height in order that you could keep your arms and wrists straight and flat.
- Sit down always with the back right.
- The monitor should be at the same height that your eyes, you can put it on a monitor stand.
- If you use the mouse many time, you should change the hand to use it.
- If you use your computer for many time you should have a break every hour, for straight the legs and move your shoulders, arms and wrists to relax it.
4. - Yes, this exercises are very good for the people that work with a computer or typewrit, because they are many time in the same position and they can have some aches in their wrists, hands, shoulders and back.
5. - No, I don´t have any exercises because I don´t work at my desk for a long time. I have some aches in my knees. If I´m sat more than a hour, I have pains in my knees, so I need have some breaks when I´m working at my desk.