Swim 3 times a week for past five years.i . Usually 2000 to 2600 and sometimes 3500. Monday swim of 3000. Felt great, relaxed and not breathing heavy. Ten minutes later entered community shower area. Stood under shower and within one minute on the floor in pool of blood. Got up left shower and then stepped back in to get soap and down again. Was told that blood presure dropped when entered shower area. I always swim early so do not eat breakfast before swim. Never had this problem. How do i prevent this from reoccuring?ityoii