GARMIN VIVOSMART 4

£119.99 The £30 seperating the two Garmin trackers in this test accounts for a few small differences and one big one – here you don’t get the GPS that the Vivosport boasts. For the money you do get a lot of other stuff though, including wrist-based heart rate monitoring as well as a Pulse Ox sensor which measures blood oxygen saturation. There’s a range of activity options including a pool-swim function and advanced sleep tracking, plus the device will also track your stress levels and ‘body battery’ to tell you whether you should train now or later. We love the Garmin Connect app for its clear design and wealth of info and this watch plays to its strengths with plenty of stats in an easy-to-read format. This was the smallest and most elegant-looking watch on test too, although even in the plain black option it may be a little bit feminine-looking to appeal to male triathletes. garmin.com