January 27, 2023 1:55 am

Differences Between BMR & RMR – How to Measure

The number of calories needed to power various bodily functions like blood circulation, temperature homeostasis, and fuel ventilation is known as the metabolic rate. The two main metabolic rates—Basal Metabolic Rate (BMR) and Resting Metabolic Rate (RMR)—are used to estimate how many calories an individual will burn while at rest for a full day. However, an approximation of RMR can be created by developing an equation using age, sex, height, and weight. Gas analysis can be used to measure BMR and RMR through either direct or indirect calorimetry. But these expressions are frequently used in the same sentence. BMR is the minimum rate of energy expenditure per unit of time for endothermic animals, including humans, when they are at rest. The main difference between BMR and RMR is that In contrast to RMR conditions of measurement, which are estimates of BMR under less rigorous conditions that can be changed and limited by the context, BMR measurements are conducted in strict laboratory settings and must achieve total physiological balance. However, while BMR and RMR have some similarities, they also differ significantly in some important ways. This article’s goal is to clarify the distinction between BMR and RMR.

What is BMR?

Your basal metabolic rate calculates the bare minimum of calories that your body requires to carry out essential tasks. These functions include:

  • Pumping blood throughout your body
  • Digesting food
  • Breathing
  • Keeping a stable body temperature
  • Growing hair and skin
  • Maintaining levels of different chemicals

70% of the calories you burn every 24 hours come from your BMR. Other ways your body uses calories include exercising and moving your body.

Your BMR depends on a variety of factors, including your height, weight, age, gender, genetics, and other factors. Your weight which is not made up of fat, particularly your muscles, is the main factor.

How Do You Measure BMR?

Estimate with math. Several equations can be used to calculate your daily BMR. The Harris-Benedict equation is one of these equations, which computes your BMR by factoring in your height, weight, age, and gender. Online BMR calculators that employ these equations are available.‌

You might get different results from various equations, and the accuracy of these calculations can vary.

Take a test. Having it tested in a lab is the most accurate way to determine your BMR. A special mask called a calorimeter that covers your mouth and/or nose will be used to capture your breath. The mask measures your calorie burn by taking into account your breath rate.

For an accurate BMR measurement, you’ll need to spend the night at the lab. Your BMR can be impacted by factors like how long you sleep for each night and the room’s temperature.

A minimum of 12 hours before, you might need to refrain from eating and exercising. Both of these actions result in gradual calorie expenditure.

What is RMR?

The quantity of energy required by your body to maintain function while at rest is known as your resting metabolic rate. RMR takes into account additional low-effort daily activities in addition to fundamental bodily processes. These activities include:

  • Eating
  • Walking for short periods
  • Using the bathroom
  • Consuming caffeine
  • Sweating or shivering

How Do You Measure RMR?

The same equations you would use to determine your BMR can also be used to estimate RMR. The same kind of calorimeter can be used for a lab test as well.

, Tu t……….. t Most likely, you’ll take the exam while standing still in a well-lit environment.

Difference Between BMR and RMR

Conditions of Measurement

BMR is measured under very restrictive conditions.

RMR is measured under less restrictive conditions compared to BMR.

Requirement of a Thermal Neutral Environment

BMR is measured under a thermal neutral environment, and it also needs a proper testing facility.

RMR is not measured under a thermal neutral environment, and it also does not need a proper testing facility.

Requirement of An 8 Hour of Sleep before Measurement

BMR needs the subject to have at least 8 hours of sleep.

RMR does not need the subject to have at least 8 hours of sleep.

Requirement of Twelve Hours of Fasting

BMR requires the subject to fast for twelve hours before measurement.

RMR does not require the subject to fast for twelve hours of fasting before measurement.

Cheaper Measurement

BMR assessment is more costly than RMR.

RMR assessment is cheaper than BMR assessment.

Realistic and Easy Measurement

BMR assessment is not an easy, and realistic measurement compared to RMR.

RMR assessment is an easy and realistic measurement compared to BMR.

Calorie Estimations

BMR is slightly lower than RMR.

RMR is slightly higher than BMR.


BMR is more accurate than RMR.

RMR is less accurate than BMR.

Other Names

BMR is also known as Baseline Energy Use.

RMR is also known as Resting Energy Expenditure.

Similarities Between RMR and BMR

Both your BMR and RMR account for the calories your body burns when you are not exercising. Typically, each person has about the same number.

Fitness. You can determine your overall metabolism using both your BMR and RMR. Your body burns more calories each day when it has a higher metabolic rate. If you are physically fit, both your BMR and RMR are likely to be higher.‌

Total daily energy use. Your total daily energy expenditure, or TDEE, is the total amount of calories you burn each day. Your TDEE consists of calories burned through rest, exercise, and digestion. ‌ 

The number of calories you burn while at rest in your TDEE can be represented by either BMR or RMR.


Calculation Formula

BMR: Harris-Benedict equation

  • Women: BMR = 655 + ( 4.35 x weight in pounds ) + ( 4.7 x height in inches ) – ( 4.7 x age in years )
  • Men: BMR = 66 + ( 6.23 x weight in pounds ) + ( 12.7 x height in inches ) – ( 6.8 x age in year )

RMR: Mifflin-St Jeor equation

  • (RMR) kcal/day: (males) = 9.99 x weight (kg) + 6.25 x height (cm) – 4.92 x age(years) + 5;
  • (RMR) kcal per day: (females) = 9.99 x weight (kg) + 6.25 x height (cm) – 4.92 x age (years) – 161.

How to Use BMR and RMR to Improve Your Health

Your BMR and RMR can both be helpful tools for enhancing your health. You can tailor your exercise and diet to achieve your fitness goals by being aware of how your metabolism functions.

Work your muscles. Your BMR or RMR measurement is influenced by your muscle mass. Your muscles are where the majority of energy transfers occur during metabolism.‌

As you gain muscle mass, your BMR rises. During a weight-training regimen, you can keep tabs on changes in your BMR. This can assist you in figuring out how much muscle you need to burn more calories while at rest.

Plan your daily caloric intake. Eat fewer calories per day than your body requires in order to lose weight. The majority of those daily calories are made up of your BMR. Knowing your BMR can help you determine how many calories you need to consume each day in order to lose or maintain weight.


In conclusion, the BMR and RMR are two metabolic rates that predict how many calories a person would consume if he were to spend a full day resting. It stands for the bare minimum of energy needed to keep your body in working order.