What is Basal Metabolic Rate?

By Dr Harry
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This is a bit of a mouthful, but let me break it down one word at a time.

“Basal” means baseline or minimum. 

“Metabolic” refers to all the chemical reactions going on in your body which keep you alive. For example, heart beating, lungs breathing, brain thinking, stomach digesting and so on.

“Rate” is to do with measurement of time. This is usually per minute, per hour or day, but it could be calculated for any time period.

So the Basal Metabolic Rate is the baseline, or minimum, energy your body needs to carry out all the vital functions to keep you alive every day. 

Remember that whenever people measure things, they want to make sure other people measure in the same way so all the results can be compared properly. So there are standard rules for measuring the Basal Metabolic Rate. These are:

• You have to be rested - a good night’s sleep (at least 8 hours) is enough
• You have to measure it on an empty stomach (at least 12 - 14 hours after your last meal; e.g. before breakfast)
• You are lying down at rest (but not asleep), with no mental stress (which may be difficult to achieve!)
• You should be in a room where you are not spending any energy keeping yourself warm or cool (i.e. temperature neutral)

After measuring the basal metabolic rate we express the BMR as a unit of energy (e.g. kilocalories or mega-joules) per day.

You may have guessed that not everyone will have the same BMR because everyone is different in terms of their body size. The following factors will affect BMR.

Body composition. Muscle needs more energy to function than fat. So a more muscular person will have a higher BMR than someone with less muscle. 

Age. Basal metabolic rate in children is higher, because of the energy needs (for growth). As we get older and stop growing, BMR decreases.

Gender. BMR is higher in men than in women, since men have a higher amount of muscle and muscle needs more energy to function than fat.

Body size.  A tall person has a higher BMR than a short person.

BMR for the average, healthy adult is usually between 1,200 and 1,800 kilocalories (kcal) per day.

Since the guideline daily amount of energy intake is only around 2000 kcal (for women) and 2500 kcal (for men) you can see that BMR accounts for the majority of a person’s daily energy requirement.

To calculate the basal metabolic rate (measured in kcal per day) use the formula

Women: {9.99 × weight (kg)} + {6.25 × height (cm)} – {4.92 × age (years)} – 161

Men: {9.99 × weight (kg)} + {6.25 × height (cm)} – {4.92 × age (years)} + 5 

So for a 23 year-old woman who is 163cm (5’ 5”) weighing 65kg (143 lbs) her Basal Metabolic Rate is:
(9.99 x 65) + (6.25 x 163) – (4.92 x 23) – 161 = 1394 kcal/day.

We have prepared a calculation spreadsheet for you. Download, save and use!  

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basal_metabolic_rate.xlsx
File Size:	242 kb
File Type:	xlsx

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​What does the BMR number tell you? Well, most people do more than just rest in a day. So the more active you are the higher your metabolic rate. If you are trying to lose weight, a calorie intake exactly equal to your BMR would mean that your consumption is exceeded by what you are burning in a day and weight loss will follow. The more active you are the higher this difference will be and the faster you will lose weight. 

​Although your personal finances and your business success are my primary interest, I believe you only operate at peak efficiency when you're fit and healthy. If you feel good, it filters through to your work. To help you with that, click for your free ebook: The Quick Guide to Sexy
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