Half Life 2 causes motion sickness?

There has been reports that those playing HL2 are getting sick... from motion sickness! In my years of gaming, I've only encountered this problem when I played the classic Dark Forces. After that, I guess my body somehow got used to it. I've also met many non-gamers complaining of motion sickness when playing, or even looking at FPSes. Now, it seems like the realistic graphics of HL2 is bringing up this problem for many, some of them veteran gamers. I've not got around to playing HL2, as I'm still on Doom 3, but will certainly be wary of this problem when I check the game out.

There has been numerous reports from gamers who has experienced motion sickness in Half-Life 2, even those who play tons of games and never experienced this issue. Some people theorize that it is caused by the frame of view being set to 70 (as a reference, most FPS games have it set to 90.) Others say it’s caused by the default low refresh rate, and still others think it’s the physics of the world seeming to be so real.