Why is Training effect wrong sometimes??

I have the same problem, I use a Garmin forunner 735 connected to a Decathlon Chest HR monitor, I mostly run and do bike rides. I would say 95% of the time I get a figure for the training effect, but sometimes, it strangely gives me a figure of 1, even for a 1h30 bike ride a 156BTM average. I don't understand how it could be the equipment, because it's calculated from HR data which comes through ok, but I would be interested to know if others have found that changing HR monitor fixes this problem?

It does this to me all the time. My standard 30 row on a concept 2 is about 500 calories and training effect between 3.5 to 4. But today for example the same row is showing as 200 calories and t/e of 1. I'm wearing a heart rate monitor and that always tracks as  normal. It's nothing related to the heart rate, just an annoying bug. Surprised Garmin can't fix something so simple. 

Hi. I have a phenix 3hr. Problems with wrong calculation of calories and training effect happens every now and then and is very annoying. The problem is not my hr-band which is now brand new with new battery. Has happened before also with different bands and good battery. 

I can't find a better reason than a bug that Garmin should try to fix asap! 

If reason is missing data maybe it's still stored in the watch and a refresh or sending data again would help, but don't think this is possible to do. 

Last cross country trip I went 40km and calculated with 78jg and 138 average hr I should burn roughly 2500-3000 kcal. But the stupid workout summary says training effect is 1 and calories burned is 700!

Please anyone, you know how this can be fixed? And please can someone from Garmin give us an update on what's it all about, as you surely have this problem on your list already and have some some research on it.

Besides this I love Garmin and couldn't live without it

Much appreciated! 

Anders

And please can someone from Garmin give us an update on what's it all about, as you surely have this problem on your list already and have some some research on it.

Hard to tell whether Garmin is aware of any problem at all. If you only posted it here, on the user forum, and did not contact the Support, and nobody else did, then do not expect they would find it and answer your questions here. You need to open a support ticket, and hope others having similar problems will do it too, so that the engineers at Garmin see that it is a frequent problem, and have better chance to track it down. Personally, I did not experience any such troubles yet, but at those who did, the restart of the watch often helped (at least intermittently).

I have a Fenix 3HR and a Garmin ANT+ heart rate strap.  My strap battery was running low and for a week or so gave alternating ultra low and ultra high readings.  My calculated max heart rate is 158 but my erroneous high readings reported highs of 190+, a heart rate I have never come close to on my workouts.  I changed the batteries and the readings went back to normal.

Ever since the glitch my calories and training effect have been reporting way too low.  

Before the battery glitch

for a 24 km bike ride avg speed 23.7 - HR 130 avg / 148 high, 855 calories, Training Effect 4.7

After glitch

for 24 km bike ride avg speed 26.2 - HR 133 avg / 157 high, 636 calories, Training Effect 2.8

My conclusion is that my high readings have corrupted my readings database.  My question is how do I fix this? 

Figured it out.

The problem was resolved by going in to settings->system->user profile->heart rate zones on the watch itself and turning off the auto detect max heart rate. This allowed me to manually change my auto detect max heart rate of 193 to an age calculated max heart rate of 161. Being in my sixties I have never achieved a max heart rate above 159 in recent years. While the manually input rate is likely not completely accurate it is far more accurate than the erroneous, high rate that was stuck in my watch.

Interestingly, my Garmin Connect app and Garmin Connect website both have a place for input of heart rate zones.  These fields do not overwrite the settings in the watch itself, at least not for my Fenix 3HR.