What Is the Basal Metabolic Rate and What Bearing Does It Have on Fitness?

Basal Metabolic Rate (BMR) is a concept that we need to understand to better understand the working of our body and to comprehend why we weight what we do.

What Is the Basal Metabolic Rate and What Bearing Does It Have on Fitness

What is the basal metabolic rate?

Simply put, BMR is the amount of daily energy we expend when at rest; i.e. the amount of energy needed only for the functioning of the body’s vital organs such as the heart, lungs, the kidneys, liver, the nervous system, intestines, sex organs, skin and muscles.

About 70% of our total energy expenditure is done on just the life processes within the body’s organs, about 20% goes towards actual physical activity and about 10% is expended on Thermogenesis or the digestion of food.

Why BMR is important

There is the understanding that BMR relates to the amount of lean muscle mass that a person has in the body – less lean body mass is tantamount of lower BMR which is seen to decline with age.

Also knowing the body’s BMR helps to know what amount of calories the body needs when not active and what it needs if it is more active.

The BMR factor is important to try and figure out how to lose weight, particularly weight that you want to lose after reaching a plateau or a point of stagnation in weight loss. Whether your aim is gaining, losing or maintaining weight; understanding BMR can help.

The factors that impact our BMR

Genetics and gender

This is perhaps the most important determinant of BMR. Some lucky ones among us are born with fast metabolisms that allow them to eat what they want and never put on weight whereas others have the sort of metabolism that makes weight gain easy and weight loss terribly difficult. Men have more muscle mass and hence higher BMR than women and the percentage of body fat also determines what your BMR will be: lower body fat means higher BMR.


The heavier you are, the bigger you are and the more energy is needed just to maintain body weight. Also the bigger you are the greater is the body’s surface area that you likely have. All of these contribute to a higher BMR.


The older we are the less lean body mass we are likely to have. It starts to decline after a certain age, and hence so does the BMR.


This is where BMR is very important to understand and why restrictive diets and fasting do not cause weight loss. The more you restrict your diet, the lower is your BMR and hence metabolism.