Is it reasonable, that a workout in the max HR range gets mostly aerob training effect?

Hi! I'm not an expert, just a long time Garmin user that tries to understand how these devices work. First of all Garmin calculated metrics don't care about your zone settings. Zone settings are for your information only but Garmin really only use one input from you and that is the max heart rate, so whatever is anaerobic or aerobic for training effect is not influenced by the zones, but only by max heart rate and other auto-detected metrics (lactate threshold, vo2max, maybe). The other thing to consider is that anaerobic training effect is based on the rate of heart rate increase, so for example, if you start running and get gradually to high heart rate, your anaerobic training effect will be very minimal. This makes sense because anaerobic effort can only last very little (1 minute maybe) so a sustained effort of several minutes is aerobic, by definition. Another example is sprinting, but not using a chest strap, in this case the wrist based heart rate is slow to respond, so while in real life you experienced an anaerobic effort, Garmin doesn't know about it so you get aerobic training effect. Basically to get anaerobic training effect according to Garmin, you have to do very high short efforts and you have to wear a high quality chest strap and, of course, have a fairly accurate max heart rate set. Again, this is my n=1 non expert experience. Bye!