I am in my 60's, 5'4" 189lbs. Bought XXL.This my 4th bayleaf item they are high quality, fleece lined, keep you warm. Size is spot on according to their chart. Most of the time I wear L or XL, but went with there numbers and love the fit. I used to wear my husband's thermals as they were 100% cotton. And push comes to shove, probably think they are warmer. But these are by far the best brand of woman's warm wear. They are comfortable and do not pill. I wouldn't say the material is thick, but certainly better than most and pretty much all you need. Going back for a serving pair.Great product!