Is due to posts like this one that I decided to use the AntiRSI application on my mac. I installed it on my home computer a year ago, but postponed the laptop installation until now.

AntiRSI is a free software for Mac OS X that helps prevent RSI (repetitive strain injury) and other computer related stress. It does so by forcing you to take regular breaks, yet without getting in the way. It also detects natural breaks so it won't force too many breaks on you.

Rui, I wish you get well soon.