Most of us have used an online BMR calculator at some point when trying to figure out calories and the truth is those could easily be off by hundreds of calories depending upon your body. Your metabolism could increase or decrease based upon your current health, muscle mass, activity level and more.
Two standard formulas would be
The Harris-Benedict equation for BMR:
- For men: (13.75 x w) + (5 x h) - (6.76 x a) + 66
- For women: (9.56 x w) + (1.85 x h) - (4.68 x a) + 655
- For men: (10 x w) + (6.25 x h) - (5 x a) + 5
- For women: (10 x w) + (6.25 x h) - (5 x a) - 161
w = weight in kg
h = height in cm
a = age
MY RESULTSUsing these equations my RMR is 1373 and 1405. In reality with the test performed by Dr Lorenzo Gonzalez DPT, OCS at IIPTR my rate is actually 1136.
I spoke with a nutritionist after the test and found out that another important component of this test is your respiratory quotient. My respiratory quotient was .76 which equates to 19.2% carb and 80.8% fat utilization. This is pretty much where you want to be, but if for some reason you find you are burning carbs mostly carbs (an RQ closer to 1) it could explain frequent fatigue because your body requires that you fuel more frequently.
This information can also help you see where you need to make changes in your training…i.e. more muscle mass would increase an RMR and certain things like training in a glycogen depleted state can increase your fat usage.
WHAT IS AN RMR TEST?
An RMR test has you sit comfortably while a machine measures your respiration. The best tests will utilize a mask that covers your nose and mouth then allows you to breathe in and out through your mouth. The machine measures CO2 to get your results. Some places will simply clip your nose, but it’s slightly less accurate.
You fast for 12 hours prior to the test and do as little activity as possible to ensure it’s truly measuring what you would burn if completely at rest.
From there you add in your level of activity for the day and then you add in your exercise to determine your total calorie expenditure.
Next up I’ll go in to how your RMR results can then be used in conjunction with VO2 Max testing for planning your fuel strategy!
Have you ever done an RMR test? Were you surprised by your results?
I am grateful for new information on which I can take action to make changes…are all runners such number crunchers?!