T Nation

Basal Metabolic Rate?


I had my BMR tested at the endocrinologist 2 weeks ago and it came back at 2727 calories per day.

She used a breathing machine to measure the BMR and I had to breath in and out through only my mouth for 10 minutes. At first I was a bit claustrophobic, same when snorkeling, causing me to breath very fast for about 2 minutes.

Would this screw up the test and how accurate is this test?


The method you describe sounds like indirect calorimetry. While not the 'gold standard' (which is widely considered to be doubly-labeled water) it is considered to be an accurate measurement of energy expenditure, yes.

And overbreathing could affect the outcome as CO2 elimination is increased without a subsequent rise in O2 uptake. Basically the respiratory exchange ratio may change due to the altered breathing pattern rather than the effects of metabolism.



Thank you for your intelligent response. Maybe I should be retested. It would be nice to know my real BMR for when I do a cutting phase.


Hey sully's, what's the difference between that test and some of the general numbers people give for figuring bmr? Bodyweight x 15, such as that. I'm curious because I know one person that had something similar done and after using that calculation, it was very close.



I guess this type of testing is more accurate and not just a formula based on age, weight and height. Hope that answesr your question.


I think BB wanted you to give us your BMR based on bodyweightx15 so we could compare the RESULTS. I'm not sure he was talking about methodology comparisons.


Right, that. I should have just asked how much you weigh. Sorry for the confusion.


I am 68(170cm) inches tall, 200(90.9kg) pounds and 41 years old. When I used CT's calculator I came in at about 1800 calories per day.

From CT's Prime Time entry:
Your BMR is a function of your size, sex and age. It is also influenced by your metabolic status (hypo or hyperthyroid state for example). We can calculate that BMR with the following formulas (by Harris-Benedict):

For men
BMR = 66 + (13,7 x weight in kg) + (5 x height in cm) - (6.8 x age)

So for a 30 years old bodybuilder of 220lbs (100kg) on 5?11? (178cm) it comes up to:

BMR = 66 + (13,7 x 100kg) + (5 x 178cm) ? (6,8 x 30)

BMR = 2122 calories per day


JB also has an equation, using LBM % I belive.

There's a calculator on his site ( http://www.johnberrardi.com )


Yeah, but a mutiplicator is used for every activity level.