BMR and exercise?

karlokralj38

Dear,

My BMR is 1895.

after I put that I am a very active person (3-5 exercises per week) it rises up to 4400. 4 workouts, 2 swims and 2 tennis matches per week.

now my question is, if my BMR is based on those activities, should I even add them to my daily dairy or will it then count double?

Should I add that I went for a 45min swim session or is that already counted in that 4400 BMR?

Susan_RD_101

@karlokralj38

Yes, this would be double counting. I find it helpful to leave your activity to "sedentary" (unless you are very active in your job) and adding in your exercise separately.

Kind regards,

VegasTortoise

This really needs a fix IMO, reporting the "wrong" activity level to get accurate results doesn't seem right. I'm not really sedentary either and I have to do the same (set activity to sedentary) in order for the numbers to seem logical.

BMR is Basal Metabolic Rate, not really dependent on activity level but on muscle mass and anthropometry (M/F, height, weight, individual variation). This is the calories (kcals) we burn while doing absolutely nothing but sleeping and sitting. Anything above that is active calories.
Since so many other apps add "activity" calories according to steps taken and other data, BMR should be a fixed number unless a person adds/loses a bunch of muscle mass or gains/loses fat weight or grows (how I wish) in the case of teens.

In Exercise Physiology we base total caloric output for a day on:
BMR + active calories + exercise
Active calories include things like steps, shoveling the driveway, carrying the kids to the van, etc. Usually we EPs measure this via heart rate, during studies we ask participants to wear a HR monitor the entire day. Anything above sleeping or sitting is active calories.
Exercise are willful workouts, measured via another app or manual input.

Since I wear a Garmin Vivoactive3 24/7 daily, Apple Health picks up the activity level and exercise workouts from Garmin Connect and I have Cronometer set to pick up Apple Health added active calories and exercise (separately). So I set Cronometer to NOT add anything to my BMR.

fitgirl

I agree it really does need to be fixed.

Andromedus

I just picked up this thread because I learned that exercise doesn't ONLY burn calories, but it increases your BMR if you're consistent with it. In other words, if I started working out every day, I wouldn't only be adding the calories burned from the workout, I'd also be boosting my metabolism. Is this true based on what you know?

All this leads me to the question of how to get accurate readings from Cronometer...? Is there a way to "hack" it to get the accurate BMR?
Thank you, kind forum, for your knowledge.

jefmcg

Sorry, but "accurate" BMR is not possible - well, except if you spend some time in a room sized calorimeter.

Of the predictive equations tested, the Harris-Benedict equation (mean difference: -14.8 kcal/day, RMSPE: 195.8 kcal/day, mean % difference: 0.1%) was the most accurate and precise, but accuracy in prediction of the equation were only 35.7%

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3572798

That means if your BMR on the app is 2000kcal, the actual value could be anywhere from 1300-2700kcal 🤯 Exercise might change it a few percentage points, but that is just noise in that huge possible range

Susan_RD_101

@Andromedus

You'd only be "boosting" your metabolism if you're increasing your mass and changing your composition (i.e. putting on muscle). But I agree with the above, you really do need a DEXA or calorimeter to accurately measure BMR in an active person.

Kind regards,