My son is a collegiate cross country runner and this season he struggled half way through his races and couldn't complete workouts. Would lose his energy and body felt chilled. After races, he would be freezing yet sweating...even had goosebumps. We have seen endocrinologist and sports med....had over 11 vials of blood testing, CT of abdomen and everything coming back normal. Last blood test he had was ferritin serum per suggested of a couple of coaches we know and a couple of parents. This came back @ 45 which is in normal range but I have heard that elite runners should have ferritin levels above 50 and preferred closer to 70. Have you heard of this or have any suggestions? I would like to try hi mom iron or ferritin levels but want to make sure this is safe. We just know something is wrong, but no one can figure it out.