My 20 year old son is extremely heat intolerant. It has increasingly gotten worse over 3 years. This summer he can't tolerate being out in the heat at all. He has started having sharp chest pains if he has been out and then comes into air conditioning. He had an incident 3 years ago where he came home from work almost delirious and collapsed in the chair, we put ice packs under his arms and had him drink water. He spent the rest of the afternoon resting in the chair exhausted. Since then this problem has only gotten worse. I plan to take him to a Doctor this week but want to know how we should proceed?