Just a quick message to say that we have had simliar experiences to those Shaun has described.  Mark is a non saltwaster, but has shown signs of hypoglycemia since he was a todler. He is now 14 and the only times which he has problems are in extended sports activities, principally school cross country races (he plays hockey and tennis etc, with no problems).  When he was younger, the teacher in charge used to have a supply of chocolate etc, but now he takes the new sports drinks which provide glucose and electrolyte replacement.

NB His father is an insulin dependent diabetic but Mark has not displayed any signs that  have suggested to us that Diabetic testing is necessary.