How to Calculate Your Basal Metabolic Rate (BMR)

Resting Metabolic Calorie Burn and How to Improve It

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Your basal metabolic rate (BMR) is the minimum level of energy required to sustain vital functions such as breathing, digestion, and circulation—all of the bodily functions that happen beyond your control.

Your BMR is just one number you need to know if you're trying to lose weight. Losing weight is all about calories—the ones you burn and the ones you eat. All of the calories you burn in a day is known as your total daily energy expenditure (TDEE). Your BMR is one component, but other sources include non-exercise activity, exercise, and post-exercise oxygen consumption.

Measuring Your BMR

There are a large number of formulas out there for calculating your BMR, and, as always, you can easily use an online calculator to do the work for you. However, there is a common formula many experts use to estimate BMR, so get out your calculator and see what you can come up with.

Revised Harris-Benedict Formula

The BMR formulas are different for men and women and they've been revised since they were originally created. These are the revised Harris-Benedict BMR equations:

  • Male: (88.4 + 13.4 x weight in kilograms) + (4.8 x height in centimeters) – (5.68 x age)
  • Female: (447.6 + 9.25 x weight in kilograms) + (3.10 x height in centimeters) – (4.33 x age)

When using these formulas, your weight is in kilograms and your height is in centimeters and you will need to do a conversion if you normally use pounds and inches.

For example a 42-year-old male who is 5 feet 8 inches (173 centimeters) tall and weighs 200 pounds (91 kilograms) would use these numbers in the equation:

(88.4 + 13.4 x 91) + (4.8 x 173) - (5.68 x 42) = 1900 calories burned each day just to keep the body alive.

RMR vs. BMR

The resting metabolic rate (RMR) and the basal metabolic rate are two different measurements. These are often used interchangeably for other purposes, but in the fitness world, were you to get it measured in a lab setting, your BMR is much more accurate. It's actually measured in a dark room after you wake up from eight hours of sleep and 12 hours of fasting to ensure that your digestive system isn't very active. That's pretty hardcore, which is why when you see BMR, you probably mean RMR, which is much less restrictive.

Things That Influence Your BMR

There are things that will temporarily affect your BMR, such as eating spicy foods or going out in really cold weather, but there are only a few things that can affect your BMR for the long-term.

  • Age: The bad news is that your BMR will usually decrease as you age, which means many of people may need to adjust their diet as they get older to avoid weight gain.
  • Menopause: If you're going through it or been through it, you already know your BMR usually goes down during this period of time, meaning you're burning fewer calories.
  • Weight Training: Building muscle is an excellent way to increase your BMR for the long-term.
  • High-Intensity Interval Training: This form of exercise seems to beat weight training for raising your BMR.
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