Activity trackers range from simple heart rate monitors to help you pace your runs all the way through to touch-screen watches that can track your hikes, play music or even measure your blood oxygen levels. No matter what your sport, there will be a device to help your training, from altitude trackers, recording your surf session or even navigating you around the golf course. Many devices have solar charging so you can stay out longer. Several watches in this category will sync with apps, so you can keep a record of your activities or even use Google Pay to grab some groceries.