There are times when I am working out and all of a sudden I get very light headed and my hearing starts to go and then i get tunnel vision and sometimes lose the ability to form actual words. Also, my heart starts to beat a little faster and harder. I work out on the regular but it happens more when I am lifting and use more of my major muscles. When this happens I also get diarrhea and my mouth gets watery. I also get shaky, cold but sweat at the same time. I bring it up when I go to the doctors for physicals but it is always brushed off.