What is Your Basal Metabolic Rate (BMR) and How Do You Calculate It?

The term basal metabolic rate (BMR) is used to describe the amount of daily calories that your body expends when it’s at rest. Even while resting, your BMR is the largest stimulus that affects your calorie expenditure, burning up to 70% of your calorie intake leaving 20% for physical activity and 10% for food consumption.

Physical activities increase muscle mass, raising the BMR, while the loss of lean body mass, lowers the BMR. The aging process also decreases the BMR as do health conditions in relation to your body’s lean mass and metabolism.  Biological reactions to emotions, stress or illness also cause a change of input or output of energy, controlling your BMR. 

Metabolism

Metabolism is a chemical reaction in our bodies that sustains life in two process categories; the first breaking down organic matter and the second using energy to create cells needed to operate our body systems.  Both the metabolism and the BMR are influenced by a number of factors: age, weight, height, gender, environments, temperatures, dieting and lifestyle.

In younger children the metabolism tends to be higher due to the frequency of cell divisions necessary to repair or create cells in the body’s system. Over 10 thousand trillion cell divisions occur within an average lifetime. Taller and heavier individuals have higher metabolisms. Men have a 10-15% higher metabolism rate than women, due to higher amounts of lean body mass. Diet changes can lower BMR’s by 20%.  And weather temperatures can cause higher BMR’s in hotter or colder environments compared to midrange temperatures.

Calculating BMR

Here’s the BMR formula to identify the amount of calories needed to maintain, gain or lose weight.  Remember that lean muscles use more energy, so individuals who are leaner or more active burn more calories.  Whereas overweight and less active individuals burn less calories.

For men, use this formula:

• 66 + (6.3 x weight in pounds) + (12.9 x height in inches) - (6.8 x age in years)

For women, use this formula:

• 655 + (4.3 x weight in pounds) + (4.7 x height in inches) - (4.7 x age in years)

Examples for men:

• 66 + (6.3 x 225 pounds) + (12.9 x 72 inches) - (6.8 x 51 years)
• 66 + 1417.5 + 928.8 – 346.80 = 2065.5 = BMR

For women, use this formula:

• 655 + (4.3 x 150 pounds) + (4.7 x 65 inches) - (4.7 x 51 years)
• 655 + 645 + 305.5 – 239.7 = 1365.8 = BMR

BMR Activity Table

Studies show that men and women need 16 calories per pound per day to energize lean muscle.  BMR information suggest subtracting 500-1000 calories daily to lose weight and adding 500-1000 calories daily to gain weight.  As with all health issues, seek professional advice prior to making any changes to your lifestyle.

1. Sedentary: Calories = BMR X 1.2
2. Lightly Active: Calories = BMR x 1.375
3. Moderately Active (ex 3-5 days per week): Calories = BMR x 1.55
4. Very Active: Calories = BMR x 1.725
5. Extra Active: Calories = BMR x 1.9

Sources: Right Health, WebMD, Harris Benedict Equation

Photo