What heart rate is considered low aerobic?

Thanks Kalmer. Now I know why my low-aerobic value does not rise much. I just ran in low zone 3. I must say I have difficulty with Z2, because my speed drops so much I almost fall over :-)

Also keep in mind that the zones stated by Kalmer are more or less based on lactate threshold HR. The zones will only make sense for you if your LTHR is set accurately.

Garmin's classification roughly follows the zones, but is also dependent on stamina drain and exercise load (which seems roughly in line with stamina potential drain). I've done workouts that were mostly Z3 with nothing in Z4 or Z5 and still gotten threshold classification. I also don't think I've ever seen a classification of "recovery" even for a workout entirely in Z1. For me, exercise load seems to map pretty nicely to my energy level during a workout, and this especially holds true for harder workouts.

Z1/Z2 running feels like a slog at the beginning, but once you stick with it for a bit you'll notice that it gets a lot easier :) The key is consistency and to mix in a little bit of hard running so your body doesn't forget how to work at high effort

Agreed. Make sure your lactate threshold HR is set correctly. For beginners it should be roughly your 10k race avg pace and HR. If you have chest strap you can do garmin lactate threshold test but take the results with a grain of salt.

If your HR gets too high you can try run-walk method for easy runs and base runs.

To get recovery training effect workout has to be Z1 or very low Z2 and very short, about 30-35min max.

Low aerobic if you maintain <80% of max HR.

Your input for max HR is crucial. 

That explains what I've been seeing. My recovery runs are Z1 but longer than 35 min.

Keep in mind that Garmin does not xare about how you set your zones. The calculation is solely based on maxHR (and depending on the metric, also resting HR and LTHR)

For me, zone 3 and a maximum of 20% in zone 4.

I would tend to agree with this  one, but it’s obvious that nobody really knows. I find it pretty strange that Garmin does not step in and solve the matter once and for all!.

Garmin-SierraCan you?

Just my 2 cents coming into the conversation late. The most accurate way of determining your first ventilatory threshold which is often a proxy for lactate threshold is to get tested at a sports medicine institute like I did. This is when you start producing more carbon dioxide than you are consuming oxygen. The downside is that it is expensive. Alternatively, you can get a good idea of what this is by doing a heart rate drift test on a treadmill. It is obviously not as accurate but will put you in the "ballpark". Here is a video explaining how the test is conducted. https://uphillathlete.com/videos/heart-rate-drift-test/

For low aerobic training I try to stay around 70% of my max heart rate to get the best benefit.