I like it in theory, but in practice, three hours of exercise a day (for those who sleep an average eight hours) is a lot to fit in, even in smaller increments. Still, it's a good figure to keep in mind--sort of a Platonic ideal for which I should be striving, or something.
As for whether smaller units of exercise time are the same as bigger ones, I suspect not. I've got to be doing something different with a continuous half-hour of biking that leaves me sweating and shaky-kneed versus three ten-minute sessions that just make me breathe a little harder. On the other hand, I've been wrong about needing to feel the pain before I think something's working--that's why I used to deprive myself on diets.
One thing is absolutely true: whether it's two minutes at a time or ten minutes at a time or all at once, just getting up and moving is
definitely better than putting down roots.
