Lack of sweat during excercise

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?

[mandymoo1983]

i dont have an answer but i can say i am exactly the same i never sweat i do cardio everyday with heart rates of up to 190 and no sweat however i did ask my doctor if it would inhibit me losing weight and he said no some people just dont sweat.ive been thinking of using a sauna to see if i can crack a sweat maybe our pores are clogged i dont no but yes an answer would be good good luck to you.

[spade22]

Is it possible you are not hydrated enough?  I  used to only drink about 1-2 glasses a liquid a day and never sweated when I exercised periodically or even when out in the sun at 100 + degrees for extended periods of time!  About 6 months ago I decided  I wanted to lead a healthy life style (30 Ibs over weight) and started exercising daily, eating healthy foods and drinking at least 10 glasses of liquid a day.  Now I sweat very easily when I work out (this was NEVER the case previously) and will sweat within a few mins of sitting outside in 80 degree weather!  I never had any symptoms of dehydration but now believe my lack of sweat was from not being hydrated enough.
I would recommend increasing your fluid uptake and see if you notice any changes after a few days

[bxsinner81]

I am 30 years old over weight but that's my only issue everything else is healthy I work out 4 times a week I walk 3 miles every time I work out but no matter how hard I work out I just can't sweat any suggestion. Please help