From sleep to steps, the Garmin Vivoactive 4S tracks everything you need it to. Garmin packed the new Vivoactive 4S full of health monitoring features to keep you on top of your game. A wrist-based heart rate monitor keeps tabs on your effort levels during workouts, and it will alert you if your heart rate stays high while you’re at rest A pulse ox sensor gauges your blood oxygen saturation to determine how well your body absorbs oxygen Stress tracking lets you know if you’re having a calm, balanced or stressful day Advanced sleep monitoring knows your light, deep and REM sleep stages Body Battery watches you energy levels throughout the day so you can find the optimum times for workouts (and rest) Like other Garmin watches, the Vivoactive 4S has storage space for music and comes preloaded with more than 20 activity apps. Outfitted with GPS, the watch also tracks your runs to help build a digital running log. The Vivoactive 4S measures 40 mm across, and it comes with an interchangeable band so you can easily swap out colors and style. With a 5 ATM water rating—it’ll stand up to your showers and spontaneous swims—and durable Gorilla Glass 3 lens, the Garmin Vivoactive 4S is the tough and stylish GPS running watch that you’ll never want to be without.