Use the built-in LED flashlight for greater awareness when you head out before the suns up or stay out past dark. Understand your overall energy efficiency with running economy and see how much you are slowing down when your foot hits the ground with step speed loss (HRM 600 monitor required; sold separately). Running tolerance helps you understand the real impact running has on your body so you can adjust your training to avoid overload and improve. Use multi-band GPS and full-colour, built-in maps plus navigation enhancements to stay on track while you train. Forerunner 970 is ready to go when you are, with up to 15 days of battery life in smartwatch mode. If you ever go too far, use the built-in speaker and microphone to make a call from your wrist (when paired with your smartphone).Running Economy Measure your overall energy efficiency while runningusing long-term running volume, stride length and step speed loss, which tells you how much you slow down when your foot hits the g