I am 32 yrs, 5'4" and weigh apx 240lbs. My B/P, Thyroid, and cholesterol are all normal. I recently started excercising again and it seems no matter how hard I work I cannot break a sweat. I do 35-45 minutes on the treadmill and 7-10 minutes on the stairmaster. While on the treadmill, my heart rate will get up as high as 189, and still no sweat. I remember in high school, being the same way. I was very active, with softball, volleyball, weightlifting, & step aerobics, but still would not sweat. During my last pregnancy, I would be outside in 90 degree weather, 8 months pregnant and mowing the lawn, still no sweat. My face gets really red, feel a lot of pressure (slight hearing loss for a moment) and sometimes feel dizzy.
My question is, am I just one of those people that doesn't sweat, am I not working hard enough or is there a medical issue that I should be concerned about?