http://news.bbc.co.uk/2/hi/science/nature/4156692.stmMore than two years in space. The article doesn't make any mention of physical exercise. I assume the astronauts are in the space station under conditions of weightlessness?
Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)