My Symptoms Include: 1) Excessive Reaction To Heat. I Actually

My symptoms include: 1) excessive reaction to heat. I actually stand under a cold shower in the morning after exercising because my head is so hot. 2) superventricular tachycardia. My heart beats wildly and this usually happens in the morning when I am eating. I fainted last year when eating and the doctors at the ER said my vasovagal nerve is involved but they don't know why. I sit down now when I eat in the morning. 3) Tiredness and dizziness. I am a 62 year old female who exercises 3 times a week (30 minutes on an elliptical and/or one hour of yoga class or a 45 minute brisk walk). I am 5 ft. 9 in. tall and weigh 165 lbs.