Why am I so resistant to cold?

Ruth Asked: Why am I so resistant to cold?

Ok, I've seen a lot of answers to this question, but I'd like to add my own spin for this…
Pretty much all my life, I've been cold in the winter and warm in the summer, which is as it should be.I've lived in a variety of climates and always if it was at all cold, I was cold, and if it was warm or hot I was warm or hot.For I think about a year now, I've been very hot in the summer and barely ever cold in the winter.When it snows sometimes I need to wear just a t-shirt, or a light sweatshirt.This is really strange for someone who is normally cold in these temps, and everyone else is freezing and turning up the heat.
Yes, I'm female, and I'm 43 but early menopause does not run in the family or premenopause at anywhere near my age plus my menstruation is completely normal.Personally I love not being cold, but was worried something might be wrong.I just had a checkup and the doc told me not to worry about it (and I have the bloodwork to back that up), but I'd still like to know why my whole perspecive of temperature just disappeared overnight.Anybody have answers for this one?