Compositions including a polymer, a primary antioxidant, a secondary antioxidant, and a metal deactivator selected from at least one of 2,2′-oxamido bis[ethyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and oxalyl bis(benzylidenehydrazide), are disclosed. The compositions can also include a light stabilizer. The compositions can be used to manufacture insulations for wire and cable. The compositions have improved long-term heat aging and also retain their color when exposed to heat. A method of making an insulation for a conductor, such as a wire or a cable, made from a composition is also provided.