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Blog What is Basal Metabolic Rate and How to Calculate it

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What is Basal Metabolic Rate and How to Calculate it

  • by Michelle
  • July 9, 2012

 

Most people have heard the word metabolism before and have a basic understanding that metabolism has something to do with how the body burns calories.  I hear the word metabolism being thrown around a lot and it often takes the blame for weight gain (“i think my metabolism has slowed down as i have aged”) or the reason for eating more food than necessary (“it’s ok I have a fast metabolism, I will be fine”).  Although there is some small truth to these statements in certain circumstances, metabolism is not always the be all and end all of weight loss/gain.

What is BMR? This is basically the minimum calorific requirement to sustain life in a resting individual in basic processes such as respiration, the pumping of blood around the body, and maintenance of body temperature.  These are calories the body will burn on top of those burned through exercise and daily activities.  Knowing this number is a great place to start when trying to determine you metabolic rate.

It’s important to be aware of your own basal metabolic rate (BMR), as this number differs from person to person and will allow you to better asses your need for exercise and proper nutritional habits.  There are many factors that can influence your BMR such as: body composition, age, weight, gender, diet, exercise/health, endocrine glands, and body surface area.  It is hard to get an exact BMR calculation without taking lean body mass into account, but you can still get a good idea using the formula below which uses age, height, weight, and activity level.

 

Men: BMR = 66 + (13.7 X wt in kg) + (5 X ht in cm) – (6.8 X age in years)

 

Women: BMR = 655 + (9.6 X wt in kg) + (1.8 X ht in cm) – (4.7 X age in years)

 

Example:

A 30 year old female who is 5’6″ tall and weighs 120lbs would perform this calculation

BMR = 655 + 523 + 302 – 141 = 1339 calories/day

Now that we have BMR, you can calculate total daily energy expenditure (TDEE) by multiplying BMR by an activity multiplier from the chart below:

 

Activity Multiplier

Sedentary = BMR X 1.2 (little or no exercise, desk job)

Lightly active = BMR X 1.375 (light exercise/sports 1-3 days/wk)

Mod. active = BMR X 1.55 (moderate exercise/sports 3-5 days/wk)

Very active = BMR X 1.725 (hard exercise/sports 6-7 days/wk)

Extr. Active = BMR X 1.9 (hard daily exercise/sports & physical job or 2X day training, i.e marathon, contest etc.)

 

Example:

BMR: 1339 calories/day

moderately active with activity factor of 1.55

TDEE = 1.55 X 1339 = 2075 calories/day

If your goal is to lose weight, once you know your BMR you can then calculate approximately how many calories you should be eating per day and how much exercise (calories burned) you will need to do to create a calorie deficit each day.  Think of it this way, one pound of fat is equivalent to 3500 calories; therefore, if you want to lose one pound of fat per week, you will have to create a calorie deficit of 500 calories each day.  This could mean decreasing calorie intake by 500 calories, exercising enough to burn 500 calories, or finding a balance between decreasing calorie intake and increasing exercise to equal 500 calories.

 

READ MORE ABOUT METABOLISM AND HOW YOU INCREASE YOUR OWN HERE: http://www.core-condition.com/quick-tips/what-is-metabolism-and-how-to-increase-your-own/

 

Email Michelle@CORE-Condition.com for more information about calculating your own BMR.

 

Michelle Roots BA KIN, CSCS, PES, PN1

www.CORE-Condition.com