To lead a fitness-oriented lifestyle, planning your diet efficiently should be the first step. According to studies, your calorie intake is the primary precursor of issues like obesity and malnutrition [1]. The daily requirement of each individual depends on their Resting Metabolic Rate (RMR). With the help of our RMR calculator, you can figure out the optimal number of calories that you need to consume to accomplish your fitness goals.
How many calories do I burn at rest?
It is absolutely crucial for everyone to figure out their exact resting energy expenditure. That’s because it normally accounts for the largest portion of an individual’s total calorie requirements on a day-to-day basis [2].
At the same time, the knowledge has been inaccessible for a long time. Calculating precise RMR calories is difficult as the result may vary based on different factors like sex, obesity status, and ethnic differences [3][4][5]. For example, it’s scientifically proven that women tend to burn fewer resting calories compared to men under similar conditions [6].
Fortunately, our resting energy calculator takes into account the major influencing factors and provides precise values. It inputs variables like the person’s sex, height, weight, and age to offer a fair representation of their calorie requirements.
By finding how many calories your body burns at rest, you can make more efficient diet and workout programs. Doing so will also allow you to succeed in your weight loss or weight gain journey.
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What is RMR?
RMR stands for Resting Metabolic Rate. It is a measure of the number of calories that your body requires to sustain basic physiological functions like breathing, circulating blood, and regulating body temperature while being in a state of rest.
In simpler words, RMR can be defined as the amount of energy that your body needs in a resting condition [7].
On top of that, RMR can also factor in calories required for performing low-effort activities on a daily basis, such as sweating, shivering, and more.
RMR Formula
The formula used for calculating the Resting Metabolic Rate is based on the updated Harris-Benedict equation. It originally came out in 1918. At that time, it had many flaws that needed some tweaks.
Finally, in 1984, Roza and Shizgal revised the original Harris-Benedict equation to provide more precise RMR values.
According to the revised Harris-Benedict equation:
- BMR for men: 362 + (13.397 * Weight [kg]) + (4.799 * Height [cm]) – (5.677 * Age (years)]
- BMR for women: 593 + (9.247 * Weight [kg]) + (3.098 * Height [cm]) – (4.33 * Age (years)]
What Factors Can Affect Your Resting Metabolic Rate?
Finding the exact value for the number of calories burned at rest each day is difficult. That’s because the amount is based on many dynamic and ever-changing variables.
Some of the primary factors that can influence an individual’s resting metabolic state are as follows:
- Body Composition: Muscular people have a higher RMR as muscle tissues require more calories for maintenance compared to fats.
- Age: Typically, the RMR decreases with age.
- Gender: Men generally have a higher RMR compared to women.
- Genetic: Your metabolic rate can also be determined by your genetic makeup.
- Hormones: Your thyroid hormone levels can also influence your metabolic rate.
- Diet Pattern: Prolonged fasting can slow down your metabolic rate. That is why RMR tests are generally conducted after a specific amount of time has passed since the last meal.
- Body Temperature: Extreme environments can cause your body to burn more calories to stabilize your internal temperature.
- Health Conditions: Some specific conditions like Polycystic Ovary Syndrome (PCOS) can have a significant effect on metabolism and RMR requirements.
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Is RMR and BMR the Same?
No, RMR and BMR (Basal Metabolic Rate) share some prominent differences. While they both measure the amount of energy that your body requires to sustain itself and function properly, they cannot be defined in the same manner.
While the two terms are used interchangeably, they provide slightly different values. The differences arise primarily because of the distinct conditions in which RMR and BMR are measured separately.
What is the Difference Between RMR and BMR?
Superficially, you might not see a lot of differentiating factors when RMR is compared to BMR. However, they do have some glaring distinctions.
The primary caveats that separate the two terms are:
Testing Time
When RMR and BMR are being measured clinically, the time of the test can play a huge role.
Typically, BMR is measured first thing in the morning when the patient is at rest. The time frame is important because the test requires the subject to fast overnight.
RMR, on the other hand, has no time restrictions. As long as the subject has rested for 15 minutes, it can be clinically tested for precise values [8].
Testing Conditions
The conditions under which a person is tested for BMR and RMR are completely different. For BMR, the entire procedure is very rigid and strict. The test is conducted in a controlled environment, usually in a thermally neutral room.
At this time, the subject needs to be awake but in a state of physical and mental rest. It also requires that the person has not eaten anything in the previous 24 hours [9].
RMR is measured in a more relaxed environment. It allows light meals and minimal physical activities. This is the reason why RMR values are generally higher compared to BMR readings.
Precision and Accuracy
If you are looking for empirical accuracy, BMR is better than RMR. That is because it follows a very scientific method of measurement.
RMR, on the other hand, offers more relaxation that might alter the values and make the results inconsistent.
Activities Allowed
Both RMR and BMR measure the calorie requirements of a body while it is in a state of rest. However, BMR only accounts for the energy expenditure needed for maintaining physiological functions.
RMR, on the other hand, can measure the calories burned during daily tasks like sweating.
Practical Implications
In the practical sense, RMR provides a more accurate reflection of your daily resting energy requirements [10]. That is because it is measured in an environment that mirrors an individual’s daily life.
BMR’s testing process is very controlled. While that provides more precise data, the results might not provide any practical insights as the environment created for the test cannot be replicated in real life.
How to Use RMR to Lose Weight?
You can use your RMR value to devise more efficient weight loss programs. The value derived from our Resting Energy calculator is the threshold or limit that you can use for reference.
To lose weight, you need to burn more energy than your RMR reading.
But drastically cutting down on calories or over-exercising can lead to inefficient and unhealthy results. According to research, to lose weight in a sustained manner, you should be in a state of calorie deficit of around 250-500 calories [11].
This means that you need to consume 250-500 fewer calories compared to your daily maintenance calories. Your daily maintenance calories can be determined by multiplying your RMR with an activity factor
Does Exercise Increase Resting Metabolic Rate?
Yes, following structured exercise and training programs for a long time can increase your Resting Metabolic Rate. The effect is even more significant if you engage in High-Intensity Interval Training (HIIT) compared to traditional programs [12].
In each case, RMR increases because of many factors. Exercising builds muscle tissues, which require more energy than fats. Moreover, regular workouts can improve your cardiovascular health and improve the efficiency of your body’s physiological functions.
This translates to increased expenditure of energy for sustaining those functions.
Does Muscle Increase Resting Metabolic Rate?
Yes, muscle can increase your Resting Metabolic Rate. This happens because muscle tissues are more metabolically active compared to fat tissues [13].
As such, maintaining muscle mass can expend more energy, even when the body is in a state of complete rest.
Does Fasting Reduce Metabolic Rate?
Yes, fasting for prolonged periods can decrease your Resting Metabolic Rate. This is because the body interprets the situation as a state of emergency due to the unavailability of food.
As a precaution, in the long run, it starts using lean muscle for maintaining energy needs and preserves fat for prolonged sustenance. When you lose muscle, your metabolism slows down. Consequently, your RMR will also decrease.
Final Words
The Resting Metabolic Rate is an accurate measure of how many calories your body burns each day while resting. The exact value can help you become more aware of yourself and devise tailored training and nutritional programs to achieve your fitness goals.
You can also use RMR readings to prevent the health risks associated with conditions like obesity and malnutrition.
References
- Howell, S., & Kones, R. (2017). “Calories in, calories out” and macronutrient intake: the hope, hype, and science of calories. American Journal of Physiology-endocrinology and Metabolism, 313(5), E608–E612. https://doi.org/10.1152/ajpendo.00156.2017
- Astrup, A., Gøtzsche, P. C., Van De Werken, K., Ranneries, C., Toubro, S., Raben, A., & Buemann, B. (1999). Meta-analysis of resting metabolic rate in formerly obese subjects. The American Journal of Clinical Nutrition, 69(6), 1117–1122. https://doi.org/10.1093/ajcn/69.6.1117
- McMurray, R. G., Soares, J., Caspersen, C. J., & McCurdy, T. (2014). Examining variations of resting metabolic rate of adults. Medicine and Science in Sports and Exercise, 46(7), 1352–1358. https://doi.org/10.1249/mss.0000000000000232
- Astrup, A., Gøtzsche, P. C., Van De Werken, K., Ranneries, C., Toubro, S., Raben, A., & Buemann, B. (1999b). Meta-analysis of resting metabolic rate in formerly obese subjects. The American Journal of Clinical Nutrition, 69(6), 1117–1122. https://doi.org/10.1093/ajcn/69.6.1117
- Gannon, B., DiPietro, L., & Poehlman, É. T. (2000). Do African Americans have lower energy expenditure than Caucasians? International Journal of Obesity, 24(1), 4–13. https://doi.org/10.1038/sj.ijo.0801115
- Arciero, P. J., Goran, M. I., & Poehlman, É. T. (1993). Resting metabolic rate is lower in women than in men. Journal of Applied Physiology, 75(6), 2514–2520. https://doi.org/10.1152/jappl.1993.75.6.2514
- Ainsworth, B. E., Haskell, W. L., Whitt, M. C., Irwin, M. L., Swartz, A. M., Strath, S. J., O’Brien, W. L., Bassett, D. R., Schmitz, K. H., Emplaincourt, P. O., Jacobs, D. R., & Leon, A. S. (2000). Compendium of Physical Activities: an update of activity codes and MET intensities. Medicine and Science in Sports and Exercise, 32(Supplement), S498–S516. https://doi.org/10.1097/00005768-200009001-00009
- Thomas, E. A., & Bessesen, D. H. (2013). Obesity. In Elsevier eBooks (pp. 78–89). https://doi.org/10.1016/b978-1-4557-4975-1.00016-4
- Henry, C. J. (2005). Basal metabolic rate studies in humans: measurement and development of new equations. Public Health Nutrition, 8(7a), 1133–1152. https://doi.org/10.1079/phn2005801
- Compher, C., Frankenfield, D. C., Keim, N. L., & Roth-Yousey, L. (2006). Best practice Methods to apply to measurement of resting metabolic rate in Adults: a Systematic review. Journal of the American Dietetic Association, 106(6), 881–903. https://doi.org/10.1016/j.jada.2006.02.009
- Osilla, E. V. (2022, September 12). Calories. StatPearls – NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK499909/
- Wewege, M. A., Van Den Berg, R., Ward, R., & Keech, A. (2017). The effects of high-intensity interval training vs. moderate-intensity continuous training on body composition in overweight and obese adults: a systematic review and meta-analysis. Obesity Reviews, 18(6), 635–646. https://doi.org/10.1111/obr.12532
- Vybornaya, K. V., Соколов, А. И., Kobelkova, I. V., Лавриненко, С. В., Клочкова, С. В., & Nikityuk, D. B. (2017). [Basal metabolic rate as an integral indicator of metabolism intensity]. PubMed, 86(5), 5–10. https://doi.org/10.24411/0042-8833-2017-00069