Every once in a while I've found that if I stand too long, I get dizzy. Well, sure enough, 45 minutes into my dress fitting, I got so dizzy I thought I was going to pass out. Sitting down for a few minutes didn't help and we had to reschedule. The seamstress said that she sees it pretty often--and to prevent it I shouldn't lock my knees when I stand. I wasn't sure if the fix could be that simple--my Mom has also had this problem. But I talked to my fiance, who was in the military and he said that they are taught not to lock their knees when they stand at attention for long periods. So next came the all-wise internet and sure enough, there were a ton of articles about how locking your knees when you stand for long periods reduces the blood pressure back up the legs and the blood pools in the legs. To prevent this, only lock one knee at a time if you must and shift your weight often. There were even horror stories of brides passing out during the ceremony. I have my rescheduled fitting tomorrow--I hope the advice works!