This discussion has been locked.

You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Resting calories less than half of expected

On Tuesday my resting calories were 1996 (which is close enough to expected: BMR is calculated to be 1626 at a weight of 210 lbs and an estimated body fat percentage of 39%). However, on Wednesday (yesterday) my resting calories was 895 (BMR is calculated to be 1613 at a weight of 207.8 lbs and an estimated body fat percentage of 39%). With a sedentary multiplier of 1.2 I would expect the resting calories to be 1936...

In addition to updating my weight, I did adjust my activity level to 7 (since I ride anywhere from 4 to 12 hours a week), but this shouldn't reduce my resting calories. Active class wasn't set before yesterday. other variables it says it uses (age, height, and gender) haven't been changed.

Does anyone know what formula is actually being used by Garmin to approximate resting calories? Is there anyway to set our BMR ourselves?

0 seilogramp over 1 year ago

Your heart rate, max HR, resting HR, lactate threshold, respiration rate, weight, and other parameters, are all used to determine calories burned.

What is Used to Calculate Calories on My Multi-Sport Watch? | Garmin Customer Support

Burned Calories Calculated on My Garmin Device Are Wrong | Garmin Customer Support

And if you want more details: Microsoft Word - EE-white-paper_1 7 6_modified_corrected 2.doc (firstbeat.com)

0 Sojourner over 1 year ago in reply to seilogramp

Yes, this makes sense for calories burned during an activity, but I'm talking about resting calories. my device is a an edge 1040, and I don't wear a heart-rate monitor outside of activities. The only metric I record outside of activities is steps (using a pebble smartwatch) and this isn't recorded in Garmin Connect (moreover it shouldn't impact resting calories).

0 trux over 1 year ago in reply to Sojourner

The most common reason for wrong Resting Calories, especially if the difference is so important, is the wrong weight. Double check the weight, and also the units (to exclude the possibility you entered the weight in kg, while using the imperial units). Also make sure yesterday's data was fully synced. If the last sync was in the middle of the day, the overview may be showing the Resting Calories from that time (hence not for the entire day).

0 trux over 1 year ago in reply to trux

BTW, the Resting Calories are not supposed to be equal to the classical BMR (Basal Metabolic Rate). Rather they are the RMR (Resting Metabolic Rate), which is a bit higher than BMR. There are plenty of online calculators for the RMR, each giving a bit different results, but the following one gives me the value rather close to the value used by Garmin:

RMR Calculator | Resting Metabolic Rate Calculator (omnicalculator.com)

0 Sojourner over 1 year ago in reply to trux

gender, age (calculated from birthday), height, and weight are all accurate and in the correct units (n/a, years, ft & in, and lbs), last sync was a minute ago as well as just before my original post.

BMR calculation I'm using: 370+21.6*(1-[Body Fat %])*[Weight]*0.454, to get resting calories at a sedentary rate it should be 1.2*BMR.

On Tuesday the resting calories were within 50 calories of the expected (that is about 2% error from the expected resting calories). On Wednesday calories were out by a 54% error from the expected resting calories.

Today's calories are already at 1182 resting (I know this is calculating based off the partial day, so proportionally it's probably expecting a resting calories of 2026=1182*24/14 since it's 2pm for me).

stray thought: If I don't turn on my edge for a day, will it assume I don't require any calories resting?

0 trux over 1 year ago in reply to Sojourner

Sojourner said:
On Wednesday calories were out by a 54% error from the expected resting calories.

Basically, if your weight does not change, the Resting Calories are constant and do not change either. Have a look at the Calories report at https://connect.garmin.com/modern/report/41/wellness/last_four_weeks Mine is shown below - my weight is rather stable, hence the Resting Calories (blue bars) are practically constant too:

I suggest re-checking again the weight for yesterday, whether it was not accidentally changed (see the history here: https://connect.garmin.com/modern/weight/2023-09-07/2). If not, then I recommend contacting the Support. Unlike us, they have access to your data, and may see better what went wrong.

Sojourner said:
stray thought: If I don't turn on my edge for a day, will it assume I don't require any calories resting?

I do not know, but I doubt. You can try it and see.