My fiance is an ultramarathon runner. Extremely fit. He runs 15 miles like it's nothing. Yesterday he went on a standard 17-mile training run. He made it five miles and pretty much crashed. He tried to tough it out, but actually ended up getting severe diarrhea and passing out on the side of the trail for a while. He almost had to crawl the last 7 miles to his car. He says he was well hydrated. He was careful about his salt levels. He ate a good breakfast, and he eats plenty of meat (chicken, fish, beef etc). When I got home from work, he was curled up on the couch, shaking and taking frequent, sharp, shallow breaths. I asked to take him to the ER and he refused. He fell asleep for 2 hours, breathing that way, and when he woke up, he started crying(He does not cry)! He seemed to get his energy back, but this morning, the effort of getting ready for work left him short of breath, and he was complaining of abdominal pain. He went to work anyway. Help!