I'm pretty sure cold showers have been a thing to show your ability to live without comforts ever since hot showers became a possibility. And the term fits her

I'm pretty sure cold showers have been a thing to show your ability to live without comforts ever since hot showers became a possibility. And the term fits here, I believe: cold showers do very much wake you up and bring you into reality quickly. There's no dreaming about hypes when you're under a cold shower.