Zone 2 cardio rate training means working in one of five heart rate zones at 60-70% of your max heart rate. "Zone 2 is where ...

There are typically five of them. Here are Garmin’s zones, for example: Zone 1: 50% to 60% of heart rate max Zone 2: 60% to 70% of heart rate max Zone 3: 70% to 80% of heart rate max Zone 4: 80 ...