Understanding the Differences Between BMR And RMR

Both these, RMR and BMR calculator measure the amount of energy required in your body to perform function and stay alive. It measures energy in calories. BMR is the basal metabolic rate and RMR stands for resting metabolic rate.

Understanding the Differences Between BMR And RMR

Understanding the difference between these two fundamental metabolic measurements is crucial for anyone looking to optimize their fitness, weight loss, or overall health journey.

Basal Metabolic Rate (BMR)

Basal Metabolic Rate (BMR) is the number of calories your body needs to maintain basic physiological functions. These functions include; 

  • Breathing
  • Circulating Blood
  • Cell production
  • Maintaining Body Temperature. 
  • Brain Functions

BMR is influenced by factors such as age, gender, body composition, and genetics. It is important to note that BMR is measured after waking up after a full night's sleep, that is fasting for about 12 hours (fasting as in you don’t eat anything when asleep). It provides a fundamental baseline for our calorie expenditure.

Resting Metabolic Rate (RMR)

Resting Metabolic Rate (RMR) is a more specific concept falling within the scope of BMR. While similar to BMR, RMR takes into account the energy our bodies expend while at rest. The body functions include; 

  • Digestion 
  • Sitting or Lying Down 
  • Shivering 
  • Eating/Consuming Food 

Resting Metabolic Rate (RMR) is influenced by age, gender, body composition (muscle mass vs. fat), and weight. Other factors include height, hormonal levels, genetics, environmental temperature, illness or injury, dietary habits, physical activity, and stress. 

Key Differences Between BMR and RMR Rate

1. Measuring Conditions 

The primary difference between BMR and RMR lies in the conditions of measurement. BMR requires strict compliance with complete rest and is typically conducted in a controlled laboratory environment. RMR, on the other hand, allows for a relaxed state during the measurement, making it a more practical option in certain settings.

2. Factors Influencing BMR and RMR

Both BMR and RMR are influenced by various factors, including age, gender, body composition, and genetics. However, since RMR allows for a slightly less restrictive testing environment, it may vary slightly higher than BMR in some individuals.

3. Measurement Methods

The measurement of BMR and RMR can be achieved through digital BMR and RMR calculators and calorimetry, which involves analyzing the gases exchanged during respiration. Alternatively, mathematical equations like the Harris-Benedict and Mifflin-St Jeor equations provide an estimation of these rates based on variables like age, weight, height, and gender of the subject. 

Which is More Accurate?

Determining which is more accurate between BMR and RMR depends on the specific context and purpose of measurement. However, BMR is mostly considered more accurate than the RMR rate. This is possible because BMR is measured under strict conditions such as; 

  1. The subjects require a minimum of 8 hours of sleep before the test. 
  2. The measurement is taken in a dark room 
  3. A minimum of 12 hours of fasting is an important factor, meaning that you should not consume anything before 12 hours of the test.