while hiking an incline yesterday in 90 degreee weather yet shaded, I experienced light headed/dizziness, nausea and my skin became gray. I was taken to the ER & diagnosed with heat exhaustion & dyspnea (sp?) my blood pressure was high and my EKG showed some irregularities when rescue arrived but returned to normal 3-4 hrs later. something I noticed was that usually I would sweat profusely but I was not sweating at all! and today, the same thing.. no sweating as I normally would. All of my lab tests came back normal yesterday. while hiking in similar situation I would normally be soaked in sweat, I m concerned that my inability to sweat is a sign of a bigger health issue.. any ideas? I am on an extended trip & will not be back home to visit my regular dr for 2 weeks..