Wrist-based heart rate might be an easy choice when you want to move without restrictions on race day, but Forerunner 935 gives you the option to tap into much more data with the addition of a compatible heart rate strap. A chest strap heart rate monitor (like HRM-Run or HRM-Tri) unlocks advanced features such as lactate threshold and the HRV …
https://www.amazon.com/Garmin-Forerunner-Running-Unit-Black/dp/B06XGD6CS4

