Nothing feels more satisfying than turning your tracker off after a run and appreciating the miles logged on the screen. But ...

One twin followed a high-fat diet while the other ate high-carb. Their experiment will change what they eat before different activities, from cycling to a long walk.

Nothing feels more satisfying than turning your tracker off after a run and appreciating the miles logged on the screen. But how do you decide how many miles to run in the first place? There’s ...