A 2014 study from the University of Ghent in Belgium concluded that odor-causing bacteria grow better on polyester. As reported by the American Society for Microbiology (ASM), the study found that clothing made of polyester encouraged the growth of the Micrococci bacteria, which contributes to body odor.
Chris Callewaert and his team of researchers collected t-shirts from 26 people after they completed an hour-long spin session. After incubating the shirts for a day, microbes were extracted and identified. It turns out that Micrococcus, the bacteria that causes unpleasant body odor, thrives on polyester.
More troubling for the athletically active consumer, standard laundering does not always remove the pungent Micrococcus from polyester apparel. In a separate study from the University of Alberta in 2013, Professor Rachel McQueen and a team of researchers concluded that cotton fabric not only retains less odor, but washes clean more readily, as compared to polyester.
In thinking about the life span of a garment, home laundering and drying can constitute a significant portion of the water and energy in the overall product life cycle. As these two studies suggest, cotton athletic apparel, may require less water and energy to maintain which can make the garment wearable, longer.