Via luckylove who has it, and spent the day teaching nursing students what it's like. Her comment was:
The majority of students found it exhausting just to watch. That's when we said that's what our lives are like all the time. It's constant. And even when you have nothing to worry about and you've not been worrying for a few hours and you realise you're not worrying you start to worry about the fact that you're not worrying and *head explodes*
Original post on Dreamwidth - there are comments there.