Why Does The Hiking Activity Give Higher Stats Than The Walking Activity?

I suspect only Garmin will "know" why that is the case - maybe somebody from Garmin will pop up here and tell us all .  Maybe the algorithms assume that a hike will be over rougher, more uneven terrain, as opposed to a smooth path.  This is likely to be the case if it genuinely is a hike, as opposed to a Sunday stroll only a canal path or a lunchtime walk around town.  Although if this was the case you would expect the rougher terrain to cause a greater exertion and therefore higher average heart rate, and it would just be accounted for anyway as exercise load is presumably based on heart rate..  Perhaps more likely is that the algorithms may also assume you will be carrying more gear for a hike than a walk (pack, food, water, clothing etc) which would add to your overall weight, and this is being taken into account somehow.

There are so many variables involved when comparing any two activities that I would need some convincing that any such algorithm would be particularly accurate/valid.  But I'm happy to assume that Garmin knows better than I do and if I want to get the most accurate metrics for a workout I make sure to select the "correct" activity profile for the activity I am doing.  In general I feel that the Active Calories metric is at best just a reasonable estimate anyway and I only take note of it as a comparison of totals from week to week.  I doubt it is of much use as a standalone metric for any particular activity in isolation - other than justifying a certain number of beers and huge takeout after a race of course  

hiking expects harder terrain than walking thus its inherit calorie met value (used to help detemrine calories - all activiities have a calorie met value) is higher than walking - but its also based on intensity (HR) and on time - so even if time and itensity were the exact same hiking would sill have higher calories burn.

Higher training effect  - unless you were using them at the exact same time its very difficult to compare different tracks in terms of training effect as its based off your load i.e. EPOC. EPOC will change based on effort, weather, how tired your body is - so its entirely possible that one day get higher training effect & intensity mintues than when you track it another day irrespective of it being the same route.

Intnesity minutes are based off your HR - so its absolutely suggesting that your HR was higher when you tracked your hike than when you tracked your walk - so again correctly relfected in Traiing effect (as based off Load and HR) and correctly reflected in Calories burnt.

Don't see an issue here at all - based on results you have provided its all working correctly.

Calories: https://www.garmin.com/en-GB/garmin-technology/health-science/calories-burned/

Intensity minutes: https://www.garmin.com/en-GB/garmin-technology/health-science/intensity-minutes/

EPOC: https://www.garmin.com/en-GB/garmin-technology/running-science/physiological-measurements/epoc/   Load: https://www.garmin.com/en-GB/garmin-technology/running-science/physiological-measurements/training-load/

Training effect: https://www.garmin.com/en-GB/garmin-technology/running-science/physiological-measurements/training-effect-samples/ (site inclues more data on aerobic and anaerobic effect too.

KMB said:

Perhaps more likely is that the algorithms may also assume you will be carrying more gear for a hike than a walk (pack, food, water, clothing etc) which would add to your overall weight, and this is being taken into account somehow.

I think this is probably the reason, because I've done both walks & hikes at the same HR, pace, route, etc... and the hiking activity always gives a higher calorie burn and TE.

Maybe I could test this by setting my weight to say... 10 lbs. more, and doing a walk activity.