Built by a marathoner for marathoners. Combining your heart rate and core body temperature data, the app calculates your expected effort level and notifies you in real-time once you reach a new level. This helps you become more aware of your perceived effort while racing and guides you to pick an optimal race pace. You'll need to enable wrist heart rate or use a heart rate monitor strap and pair the CORE sensor with your Garmin watch to use the solution.