Too much water?
As others have mentioned, that sounds like orthostatic hypotension, not drinking too much water. That's a possibility you need to explore with a physician or NP, not a dietician. Dieticians are great but sometimes they have a tendency to assume every single physical symptom you have is correlated with what you eat and drink, and that's not exactly true.
Try pumping your legs several times before you stand up (and before you sit up from lying down). Stand and sit up very slowly. If those things help, that's another sign it might be orthostatic hypotension.
All that said, yes you can drink too much water . . . my sodium levels were low on my six month labs and my dietician advised me to not care as much about my sodium intake and to cut back on my water. I did both those things and my sodium levels popped back into the normal range. I didn't have any symptoms of it though, including dizziness or lightheadedness.
on 3/25/14 11:02 pm
64 is minimum required to prevent dehydration. you really should be drinking 100+ for weight loss. even more than that if exercising. get some vitamin water if you are having trouble, dont drink less.
I started having that within this past month or so but it was due to my iron being slightly low. I started a low dose of iron each day and I no longer experience it. I get in a minimum of 80oz of water/day, most days I get in 100oz. And I've been getting in this much since a month or two out from surgery. It is possible to wash yourself out with too much water but that would be drinking a huge amount every day and not getting in other nutrients too.