Many runners claim not to fit in the training zones when they run, or needing to walk to stay in the right heart rate training zone. I usually find it’s one of 3 reasons. 1. They only use a smart watch with wrist based HR. Through experiences, I know this is usually inaccurate. Solution: Use a chest strap or an arm strap like the one I use from Coros. 2. They don’t really know what their max HR is to calculate zones. 220-age is a starting point, but it’s almost certainly wrong. 220-61 ( my age)

What’s a Normal Heart Rate? How Do You Check Your Pulse/Heart Rate?