Running at zone 5 heart rate consider Aerobic ?

Hi, 

Aerobic Training Effect uses your heart rate to measure how the accumulated intensity of an exercise affects your aerobic fitness. It also indicates if the workout had a maintaining or improving effect on your fitness level. Steady workouts at a moderate effort or workouts involving longer intervals (>180 sec) have a positive impact on aerobic metabolism and produce an aerobic Training Effect.

Anaerobic Training Effect on the otherhand uses heart rate and speed (or power) to determine how a workout affects your ability to perform at a very high intensity. Repeated high-intensity intervals of 10 to 120 seconds have an especially beneficial impact on your anaerobic capability and result in an anaerobic Training Effect.

In the example provided above even though the heart rate would suggest a certainly high degree of effort, due to it being a steady, sustained,  significant effort the 5.0 Aerobic reading does make sense. 

When performed with a compatible Garmin device, each activity will generate a Training Effect score, along with a message that helps you understand how the activity impacted your fitness.

In general, a higher Training Effect indicates a greater impact on your fitness, to a point. A Training Effect of 5.0 can actually be harmful if reached with regularity and without adequate rest and recovery time afterward.

Your max HR may be set too low. See How can I determine my max heart rate? or HOW TO CALCULATE MAXIMUM HEART RATE WITH A FIELD TEST.

All of the zones appear to use some updating frankly. Obviously Zone 5 should be at max 5-15 minutes of top out effort not an hour. Once they establish a max heart rate, they can edit their zones in their account. Changing Heart Rate Zones in Garmin Connect

Thanks for the infos !

Thanks for the infos !