Very interesting research relating exercise with memory ability.
"When people first begin exercising, he points out, their muscles strain and burn through energy. But as they become fitter, those same muscles respond more efficiently, using less energy for the same work.
The scientists suspect that, in the same way, the spike in brain activity after a first session of biking is the prelude to tissue remodeling that, with continued exercise, improves the function of those areas."
Even a single workout may make our brain’s memory centers, like our muscles, more fit.