Guy Smarts: What the new Apple watch can do for your heart

But the Watch's development team, led by COO Jeff Williams, has tinkered with the formula to morph the wearable into an all-around health powerhouse with the Series 4, which launches today with potentially revolutionary heart features. The original version of the device didn’t have a heart rate monitor, couldn’t make calls, and lacked most of the fitness tracking features that have made it an indispensable gym companion for millions. But the Watch's development team, led by