Polymeric compositions containing additives having properties of emission and/or absorption of radiation in the long infrared region, and articles shaped therefrom are produced, including yarns and textile articles such as fabrics or knits; such additives include organic additives or inorganic fillers which have a capacity for absorption/emission of radiation in the infrared region, in a wavelength range of from 2 μm to 20 μm, and also a polymeric substrate, with the proviso that the inorganic fillers may be selected from among oxides, sulfates, carbonates, phosphates and silicates, and such inorganic fillers having an average particle size of less than 2 μm.