There are several factors why this is the case. Firstly, polyester is cheaper than cotton. it's thin breathable material is perfect for sports activities and this is also backed up by the quick drying element of the material. With the increase trend where people are joining gyms etc more people are turning towards performance polo shirts made from polyester to give it that added coolness when exercising.
Clubs are also buy the performance polo shirt printing and embroidering them with their club logo especially in the London area. The AWD COOL range which we offer have the full range of polyester material garments perfect for gym wear.