The human body typically needs a significant amount of energy in the form of calories to perform basic functions. These functions are activities such as breathing, cell production, protein synthesis, blood circulations, and others. Basal Metabolic Rate, or your BMR, is an estimate of the amount of energy (i.e., calories) that your body would burn if it were to rest for 24 hours. BMR does not include the calories you burn from daily activities or exercises.
How Basal Metabolic Rate is Measured
You should be aware of your BMR if you’re trying to lose weight. There are three ways to measure it:
- Can be tested in the lab under a restrictive setting
- Using an online calculator
- Using a formula given by scientists
The most common formula used by experts to calculate BMR is the Harris Benedict Equation. It determines your total daily energy expenditure (TDEE). Equations differ for men and women:
Men: 88.4+ (13.4 X weight in kilograms) + (4.8 X height in centimeters) – (5.6 X age)
Women: 447.6+ (9.25 X weight in kilograms) + (3.10 X height in centimeters) – (4.33 X age)
Note that the weight and height are in kilograms and centimeters respectively. You must convert if you want to use pounds and inches.
Factors Influencing the Basal Metabolic Rate
Age: BMR is great during the first few years of your life. As you grow older, your muscle mass decreases. Therefore, you need to make up for your slow metabolism by eating healthy and exercising.
Gender: Women have less BMR compared to men regardless of age. This is because women have more body fat and less muscle mass. (1)
Muscle mass: As you increase your muscle mass, the body requires more energy to perform its essential functions which will boost the metabolic rate.
Body temperature: As your body temperature increases, the body takes up more energy to cool down. High body temperature increases BMR by 13 percent for each degree in Fahrenheit.
Nutrition: The body needs to burn more calories than you consume to lose weight. If the body lacks sufficient calories, the BMR drops. To ensure that it is on track, consume a balanced diet always.
Sleep: BMR is 10 percent lower when you’re sleeping than when awake. That is because the muscles are relaxed. (2)
Activity level: You burn more calories when you are active. Indulging in exercises will increase your BMR.
Pregnancy: During pregnancy, the BMR increases especially during the last trimester where it rises from 15 to 25 percent. The increase is due to the increased weight during that period.
To reach or maintain a healthy weight level, it is ideal to know how BMR works and the total number of calories you burn every day. With that information, it’s easier to determine the changes you need to make in your lifestyle. It is also best to ensure that you track your BMR before embarking on a new diet or a new exercise program. This move will help you keep track of the results.
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- Ferraro, R., Lillioja, S., Fontvieille, A. M., Rising, R., Bogardus, C., & Ravussin, E. (n.d.). Lower sedentary metabolic rate in women compared with men. The Journal of clinical investigation. https://pubmed.ncbi.nlm.nih.gov/1522233/.
- Pacheco, D. (2020). How Your Body Uses Calories While You Sleep. Sleep Foundation. https://www.sleepfoundation.org/how-sleep-works/how-your-body-uses-calories-while-you-sleep.