Being a ball boy at the U.S. Open must be nerve-wracking enough as it is. The inner monologue goes something like this: “Am I going to get to that ball in time? That awkward squeaky noise was me, wasn’t it? Oh God, Djokovic is looking right AT me!” Now, it’s about to get even more high stakes. The New York Times reports that Ralph Lauren is providing a new form of wearable tech to the crew. The brand’s black nylon shirt will monitor the wearer’s heart rate and stress levels; the company touts it as the first garment of its type to be made by a big-name fashion brand. Going over the results of early tests, “You can actually see his heart rate spike,” David Lauren, the company’s executive vice president for advertising, marketing, and corporate communications, told the paper. “You can see his breathing.” No presh, guys.