Dehydration can cause vertigo, or dizziness, or blackout when you stand up. I think it's because not enough liquid in the system makes it hard to get adequate blood pressure to the brain. Dad (101 this year) had a couple of falls and seemed very confused, scared the sheet out of us. Turned out he wasn't drinking enough liquids, fine now.Morning @PinkyNotTheBrain and everyone. Been up all night? I had to take the day off work to bring the wife to the doctor. She's off balance and dizzy. Plus I got another leak in my basement This time it's under my shower drain and it's a pretty big hole