There are few — if any — types of clothing in which fashion and function being optimized is as essential as when it comes to activewear. Wearing clothes that perform as great as they look can be the difference between a so-so workout and an amazing one. And just because a separate feels great when you try it on doesn’t mean it will actually perform well when you’re sweating buckets or maintain its shape after multiple hot water washes. To find out the pros and cons of popular activewear fabrics, we turned to three sportswear experts: Alala founder Denise Lee, Michi founder Michelle Watson, and New Balance senior product manager Jeff Garabedian. We all know and love cotton because it feels great against our skin, which is why it’s such a common fabric for lifestyle apparel products, but unless it’s blended with other more technical fabrics it doesn’t tend to make for great performance garments. “Cotton can hold moisture (i.e. sweat), so you wouldn’t typically create a performance piece made predominantly of cotton unless some sort of wicking application was added,” says Garabedian. Watson echoed his sentiment by adding that she loves it for loungewear because it’s comfortable, so...