Why flying and running are related?

This comment came across on the 99s flight training mailing list. Maybe this is why flying and running seem so closely related and addictive to me?

Accelerated learning is about using deliberate brain-friendly techniques that help YOUR brain to accelerate -- understanding, absorption and retrieval. Fear makes people dumb, i.e., it shuts them down! Brilliance is about being able to multitask (which flying demands), so every new skill has to be built on in steps. BTW, when we're multitasking/splitting our attention deliberately, we're in frontal lobe and oh-so-present--- it is then we naturally get that gorgeous serotonin high in the sky.