Fitness trackers are going at each other like a bunch of feisty, windmilling bantamweights. Taking on Fitbit’s Alta HR in the battle to see how much tech can be crammed into a tiny wristband is this Garmin, the first to bring VO2 max estimates to the Vivo army. This means the Vivosmart 3 can, for better or worse, provide a good reading of your overall fitness level (marked from ‘poor’ to ‘superior’). If that’s too invasive, you can always just stick with the continuous heart-rate monitoring, automatic exercise tracking and swim-friendly waterproofing. In fact, the only thing this Vivosmart HR+ sequel hasn’t managed to squeeze into its chiselled body is GPS. We look forward to its tear-up with the Fitbits.