Being a footballer requires a seriously high level of cardiovascular fitness, strength and stamina.
In short, if you want to play at the very top you need to run... a lot.
Which is exactly what Alexis Sanchez is doing on international duty for Chile. Despite being at peak physical fitness, the 28-year-old still manages to run himself utterly breathless.
Given how many hours the forward spends in the gym, and his constant ability to bully and run teams ragged, it seems inconceivable that Sanchez could ever be out of breath.
Yet while preparing for Chile's friendly against Russia ahead of the 2017 Confederations Cup, Sanchez looks completely beat.
Following a running session, Sanchez signals to the cameraman 'no more' while slowly removing his top.
If he could speak he probably would, but he's just that out of breath.