I posted on here earlier this week ( http://www.letsrun.com/forum/flat_read.php?thread=8484043 ) about some weird episodes I've been having at the end of my races. A doctor I saw thinks I have something similar to POTS (postural orthostatic tachycardia syndrome). He said to drink a lot, generously salt my food, and he also prescribed me fludrocortisone (florinef I think). Anybody have any experience with POTS and running?