“To faithfully re-create low-gravity workouts, we would need to run straight up a wall, like the cartoon Roadrunner, and weight train in bed.” According to experts, long hours of sitting are not dissimilar, physiologically, to floating in space. That explains why some people think the astronaut workout is out of this world. WaPo (Gift Article): To counter the effect of sitting too much, try the astronaut workout. (This sort of takes the fun out of getting high.)