WASHINGTON — The U.S. Open, which began at Flushing Meadows this week, will test not only the world’s best tennis players, but also the latest in wearable technology.

CNET reports that Ralph Lauren is introducing a high-tech shirt that works like a fitness band without going around the wrist. The Polo Tech compression shirt has sensors sewn into it that can monitor such health indicators as stress levels, calories burned and breathing and heart rates, feeding data into an iOS app.

The shirt is being introduced slowly at the U.S Open: No players will wear them during matches.

Marcos Giron will play some practice rounds with the shirt, using the readings to make adjustments to his game.

You can see the wearable technology in action on the sides of the courts — some of the ball boys will wear the new shirts. Look for males (the women’s shirts aren’t ready yet) wearing tight black shirts with a yellow polo-horse Lauren logo, rather than the usual polo shirts.

Lauren is partnering with the tech company OMSignal on the shirts. The data recorder can be ordered now; the shirts should be available for men and women by the end of the year, and they’ll be OMSignal products without the Polo logo.

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