Dr Asha Chesnutt, who works on Apple’s clinical team, explains how the cycle tracking is at the heart of the health app.

The man behind a program that lets you trick apps like Strava with fake workouts is trying to make a larger point. “I feel like I’m poking at a very real problem,” he said.

The UGREEN FineTrack Smart Finder has a little loop on the edge which can be placed on any keychain. You can also stick one ...