Thats the most crazy/silly thing i read," to pervent fogging you have to be in good shape".... lol... I sweat a ton but my lens does not fog up because of it, before you turn on your headset, its cold, it takes time to warm up,, if you put it on your warm face while its still cold, its gonna fog up cause you have cold and warm air stuck between your face and the hmd with no air flow, when you have hot and cold temps it creates moistures thats fogging up the lens, to stop this , let your hmd warm up before you put it on(let it idle for a few minutes after you turn it on