Loads aren't making sense (Fenix 6 pro)

@Garmin - Chris BUMP

Looking at your average cadence and elevation loss, I am guessing that there was some freewheeling/coasting happening during your gravel ride.

Versus I am assuming pretty constant effort during your run.

This impacts on your aerobic load.

Also, indoor treadmill activities (and indoor rides) tend to be hotter and sweatier than outdoor rides, where you get the evaporative effect of moving through the air. This means your heart rate will typically be higher for indoor workouts than the same effort outside, which may inflate the TE for indoor activities.

Federonic said:

Loads are completely off, basically the same

I wouldn't say that they are basically the same, 137 vs 170 is a 24% increase. The anaerobic is 2.0 vs 0.5 on a 5 grade scale. The beauty with long rides is that you can keep the overall level down (which gives you Base as primary benefit) but still do some parts with a high intensity which your anaerobic fitness will benefit from.

As an opposite you can do running intervals with a low average HR and the majority of time in your lower zones but still get VO2 as primary benefit.

Exercise load uses the activity data to estimate the post exercise oxygen consumption, the recovery need, and isn't just a measurement of time and average HR.

https://support.garmin.com/en-US/?faq=YhApFCgKQN64763OBiHGf5

https://www.firstbeat.com/en/science-and-physiology/epoc-and-training-effect/

Federonic said:

So you're telling me an exercise that I burned 1600 cals has only a 20% increase in load vs an exercise with 500 cals burned?

Yes, it is two different metrics. Calories burned has to do with intensity (HR) during the activity (time) i relation to your fitness (VO2) and weight. Exercise load has to do with the recovery demand (the extra amount of oxygen required for your body to recover from the exercise).

There are plenty of articles to read on the topics, not only from Garmin. 

 It's just crazy for me to believe that the recovery load is similar in a 7k zone 2 treadmill run in 18c air conditioned room vs a 3 hour 45 minute gravel bike ride in 30 degree heat/ 80% humidity with long dreadful climbs even after losing 3L of water.

Federonic said:

It's just crazy for me to believe that the recovery load is similar

It isn't. From an EPOC standpoint it is 24% higher for the bike ride compared to your run.

Thanks for taking the time to shed some light on this !

On the other hand, it is a 37% (Load) increase from the run to the bike workout. 
Although Garmin states “Exercise Load is useful for measuring the intensity of different workouts compared to one another. In general, higher loas numbers equal more impactful training”, the 2 workouts to have the same Base Aerobic impact (of 3.6).
So, I would say that values are not “way off”…