A temperature-regulating garment and air exchange system including a fabric composed of a background yarn (11) which is visible on the rear and a base yarn (12) which is visible on the front of the fabric, and a third yarn (2) which allows the construction of a structure which lends the fabric the desired performance characteristics. In particular, in a zone designed to absorb and expel perspiration and be breathable, the garment features a fabric structure obtained by machining the background yarn and the base yarn with a looser knit with respect to other portions in which such performance is not required, so as to permit good passage of air, and the third yarn is added by inserting the yarn into a portion of row of knitting which is clearly defined in terms of the width thereof and which corresponds to the width of the breathable area to be obtained.