I suspect it is his amazing breath control and singing technique that allows him to dance so vigorously across the stage yet still retain sufficient air flow and energy to sing when he wants and how he wants. I don’t doubt that sort of physicality is tiring, especially in the context of a 4hour concert, but he is so good at minimising the air he needs to achieve musical notes, it’s as if he can compartmentalise his lungs so that half are for the oxygen needed for his leg and arm muscles and half are for his throat & singing.
