How the Apple Watch defined modern health tech

In my humble opinion, the Series 4 was a watershed moment in wearable tech history. | Image: Cath Virginia / The Verge, Getty Images

This is Optimizer, a weekly newsletter sent every Friday from Verge senior reviewer Victoria Song that dissects and discusses the latest gizmos and potions that swear they're going to change your life. Opt in for Optimizer here.

You can trace the state of health tech today to a single gadget: the Apple Watch Series 4.

Back in 2018, smartwatches and fitness bands focused on a handful of things...