Black might seem like a bad color for workout garb because dark fabric soaks up the sun's rays, making the wearer hotter. But don't sweat it, the Army ran some tests and it's okay. As Joe reports:
The Army studied whether a black uniform would make soldiers hotter but tests using a "sweating mannequin" showed the moisture-wicking material compensated for the color difference, Mortlock said.
Translation: You'll be hotter, so we'll get rid of the sweat so you won't notice how hot you are.
Also, they got rid of reflective material on the fabric, calling it a security issue for deployed soldiers. All things considered, a black uniform with bright yellow flashes stands out pretty well in the daytime and likely presents as much of a visual signature as any reflective coating would. And, really, doesn't any grown person running with a t-shirt tucked in to their shorts already stand out?
You can use the $3 the Army saved you in dumping the reflective material and spend it on the reflective belt you're going to need.