As I understand it, the 4 hour limit has to do with learning at your greatest rate possible. Most of us don't operate at maximal learning all the time, or even very often/
The mind conscious, or otherwise, still has physiological limits. The 4 hour limit shouldn't be expected to be a universal global constant for all people. Some variance is a surety. Also it may be possible to increased your capacity true appropriate nutrition and training. The body does adapt to it's environment.
I think that normal academic studying shouldn't be considered maximal neuro-transmitter depletion activity. And it's be long know that many breaks make for better studying. The problem most students have is ENDING the breaks.
