PV Sindhu in action. (Photo credit: Screengrab/Badminton photo) In her iconic yellow outfit from Rio, PV Sindhu was leading India’s charge at the Uber Cup. But it was a blue-grey stick-on dot next to her eye that caught the attention as Sindhu won her opener 21-13, 18-21, 21-17 on Friday. A wearable technology tracker, it’s called the ‘Temple,’ and Sindhu has been using it in training for the past few weeks and strapped it on in a match for the first time on Friday as she battled Line Christophersen at Horsens, Denmark. Where an eye-liner or mascara would be was the ‘Temple’, a device not unlike the ‘Whoop’ or ‘Catapult’, but specifically claiming to track blood flow to the brain in real time. While still a Beta version, Sindhu has been testing the wearable that gauges neurological metrics, tracking cognition and ageing. It is supposed to track circulation through the brain, but very little is known of its exact utility in the performance monitoring of athletes.…