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What is an RMR Test? Here’s Everything You Should Know

Updated: May 14

What is an RMR Test? Here’s Everything You Should Know

Picture yourself sitting in your favorite coffee spot, enjoying your morning drink, when your friend mentions something called an RMR test. You listen, but deep down, you're puzzled, wondering, "What is an RMR test?" It's a question that might have crossed your mind before, but you never really got around to asking.

To put it simply, an RMR test checks how many calories your body burns when you're completely still. It's like peeking into how much energy your body uses just to keep you alive—like breathing, keeping your heart beating, and staying warm.

In this blog, we'll thoroughly explain what an RMR test is, how it works, and whether it could be worth considering. 

What is an RMR Test?

An RMR (resting metabolic rate) test is a simple and painless procedure that helps determine how many calories your body needs to maintain basic functions like breathing, circulating blood, and keeping your organs working while you're at rest. 

It's usually done in a clinic or lab setting, where you'll be asked to sit or lie down comfortably for about 10 to 15 minutes while your body's oxygen consumption and carbon dioxide production are measured.

How Does RMR Testing Work?

How Does RMR Testing Work?

During an RMR test, you'll typically breathe into a mask or mouthpiece connected to a machine called a metabolic cart. This machine analyzes the air you breathe in and out to calculate how much oxygen your body is using and how much carbon dioxide it's producing. 

Based on these measurements, the test can determine your resting metabolic rate, which is the number of calories your body burns at rest.

Steps of RMR Testing

The entire test typically takes around 15 minutes. Here's a quick rundown:

  • Prep Time: You'll need to fast for a few hours (usually 8-12) before the test and avoid strenuous exercise. A relaxed state is key for accurate results.

  • The Test: You'll rest comfortably in a chair or lie down in a calm environment. You'll wear a mask that gently collects a breath sample.

  • Science at Work: The magic happens behind the scenes. The machine analyzes the oxygen you consume and the carbon dioxide you release to calculate your RMR.

Once you have your RMR, some facilities might add an extra calculation to estimate the calories you burn through daily activities and digestion.

Difference Between RMR and Total Energy Expenditure

The way your body uses energy can be split into three types of calories. When you add up the calories from each of these groups, you get your total metabolic rate.

  • Resting Calories: These are the calories burned while your body is at rest, just keeping you alive. This is the biggest chunk of your total calorie burn, about 70-80%.

  • Activity Calories: These calories are burned during everyday activities like walking, eating (digesting food), and typing—anything you do in your daily life that's not formal exercise.

  • Exercise Calories: These are the calories you burn during intentional exercise, like jogging, lifting weights, or doing yoga.

Total energy expenditure is the sum of all these calorie groups, showing how many calories your body uses in total each day.

How to Prepare For Your Test

How to Prepare For Your Test

Here's how to get ready for your test:

  • Don't eat or work out 4-5 hours before your test.

  • Avoid having coffee for 4-5 hours before your test.

  • Skip smoking or drinking alcohol 2 hours before your test.

  • Don't do intense weight training for 12 hours before your test.

  • Make sure you're well-rested and relaxed when you arrive.

Are RMR Tests Accurate?

RMR tests are considered a highly accurate way to measure your metabolic rate, with an error rate of less than 1%. They're much more reliable than online calculators that estimate your RMR based on general formulas.

There are two main ways to do RMR testing: 

Indirect calorimetry is seen as more precise but might be a bit pricier. A study review in the Indian Journal of Endocrinology and Metabolism showed that while other tests aren't perfect, indirect calorimetry is great for understanding your body's needs and handling health problems over time.

So, is an RMR Test Worth It?

An RMR test can be a valuable tool if you're looking to:

  • Lose Weight: Knowing your exact RMR helps you set realistic calorie goals for weight loss.

  • Gain Muscle: Building muscle mass can increase your RMR, helping you burn more calories at rest.

  • Optimize Nutrition: Understanding your RMR can help you tailor your diet to your specific needs.

Let's Use an Example in Case of Losing Weight

Say your total metabolic rate is 2400. If you eat exactly 2400 calories every day and don't do anything else, your weight will stay the same. You won't gain or lose any pounds.

But if you want to lose weight, you need to eat less than 2400 calories. To do this in a healthy way, most experts suggest having a calorie deficit of 500 calories each day. This means you'd lose about one pound per week.

To create that deficit, you can either eat 500 fewer calories every day or eat 250 fewer calories and burn 250 calories through exercise.

Check out our informative blog to learn, “How much does an RMR test cost?

What else does the RMR test tell you?

What else does the RMR test tell you?

In addition to revealing how many calories your body burns at rest, the RMR test also tells us about your respiratory quotient (RQ). This shows whether your body mainly uses carbs or fat for energy.

Knowing this helps your nutritionist decide if you need more carbs or fat in your diet. If you want to lose weight, it also helps them suggest the best type of diet for you—like low carb, low fat, or a combination.

It’s Not a Once-and-for-all Test

The RMR test isn't a one-time thing. Many people believe that their metabolism stays the same throughout life—either fast or slow—but it actually changes based on things like muscle mass and other factors. 

If you change your muscle mass through training or weight changes, it's a good idea to redo the RMR test. It's recommended to do a resting metabolic rate test every 3-6 months, especially if you lose a lot of weight. 

Besides, you can check out our informative blog to learn how to make a meal plan for weight loss and muscle gain

Why choose Back Bay Fit?

In Boston, our RMR test shows how many calories your body burns when you're at rest. This helps us make a personalized diet plan for weight control and overall health. 

We also provide AMR analysis to see how your body uses calories during activity, VO2 Max testing to check your oxygen use during exercise, and WHOOP calibration. 

Book a free consultation now to find out more.

Also, are you curious about the perks of personal training? Check out our informative blog to learn about the benefits. Plus, see what top Personal Trainers in Boston can provide you in the realm of personal training.

Wrapping Up

To sum it up, knowing "What is an RMR Test?" helps us understand how many calories our body needs and how it works. With this understanding, we can plan our diet, exercise, and overall health routines better. Whether you want to lose weight, get fitter, or just stay healthy, the information from an RMR test is super helpful. 


Where can I get an RMR test?

You can get an RMR test at many hospitals, wellness centers, and even some gyms! Just search online for providers in your area.

How long does an RMR test take?

The actual RMR test is quite quick, typically only taking 15-30 minutes. There might be some extra time for setup and result explanation.

What is a normal RMR level?

A normal RMR range is quite broad, from 1,200 to 2,000 calories per day for adults, with individual factors like muscle mass playing a big role.

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