I was starting to see black shadows moving in my peripherals and it was literally like my batteries were dying, I kept getting "stuck" and I got really dizzy and had to have hubby come help me to bed. I'm fairly positive that is the longest I've ever gone without sleep (and only 3 hours of it before being awake for a full 33 hours) and I never want to go through that ever again. Still feel really off but that 4hours helped a lot. 3 hours of sleep in a 57 hour period is not a good time and it was incredibly frustrating to be so exhausted yet so not tired for so long. 0/10, do not recommend.