As a society we have become obsessed with metabolism and how to control it in order to manipulate the calorie-burning process. Most of us associate boosting our metabolism with losing more weight, burning more body fat, and increasing lean muscle mass. Resting metabolic rate also referred to as (RMR) and Basal metabolic rate (BMR) play an important role in defining a baseline measurement or benchmark of how many calories you naturally expend to set and reach your body composition goals. Often used interchangeably there are differences between BMR vs RMR. We're going to learn about the purpose of BMR and RMR and also the differences to help you start your fitness journey. 

What Is Metabolism and Basal Metabolic Rate (BMR)?

Before you can understand BMR we need to first address what metabolism is. Metabolism is a culmination of biological functions taking place within your body. These functions include things such as converting the food you eat into units of heat or energy otherwise known as calories. Calories fuel basic biological processes like breathing or moving. The rate at which these important biological events occur is known as your metabolic rate.  

Your metabolism is calculated using what’s called Total Daily Energy Expenditure (TDEE). TDEE is comprised of three key components; resting metabolic rate (RMR), the thermic effect of food (TEF), and the thermic effect of physical activity (TEPA). TEF is the energy expended when chewing, swallowing, digesting, and absorbing food. TEPA is the energy of activity, during and not during exercise.

You can measure your TDEE by using our calculator here Total Daily Energy Expenditure (TDEE) Calculator

What Is Resting Metabolic Rate (RMR)?

Resting metabolic rate is defined as the energy required by your body to perform basic functions at rest. Some of these essential functions include basic brain processing activities, blood circulation, sleep, nutrient absorption, digestion, temperature regulation, and breathing. RMR represents the minimum amount of energy required to keep your body functioning and you, alive and breathing. 

What Is Basal Metabolic Rate (BMR)?

Often used interchangeably with RMR, your basal metabolic rate is defined as the minimum number of calories your body burns to exist without any other outside influences.

Why Do You Want To Know Your BMR and TDEE?

By determining your basal metabolic rate and your total daily energy expenditure, you can accurately predict, how many calories you need in order to maintain your weight, lose weight or build more mass. Knowing how many calories you naturally burn will provide a baseline to accurately calculate how many calories you need to consume.

IF YOU WANT TO LOSE WEIGHT, then you’ll need to be in a caloric deficit.

IF YOU WANT TO GAIN WEIGHT, then you’ll need to be in a caloric surplus.

So what does it mean to be in a caloric deficit or surplus? Determining your metabolic rate, and the total number of calories you burn each day will provide you with a caloric benchmark. After you find that benchmark you now know that in order to lose weight, you need to consume fewer calories than your total expenditure. Of course, this takes into account TDEE, which also includes any additional burned calories from activity.   

The Science of Metabolic Adaptation

As you begin to track and optimize your metabolism, it’s important to understand that your body is incredibly adaptive — especially when under stress from dieting or overtraining. This phenomenon is known as metabolic adaptation, or "adaptive thermogenesis."

According to a study in the American Journal of Clinical Nutrition, prolonged caloric restriction can cause your body to decrease resting energy expenditure by as much as 15% to 30% (Rosenbaum & Leibel, 2010).

This is why incorporating refeed days, diet breaks, and reverse dieting phases can be beneficial — not only to maintain performance and mental clarity, but also to prevent your BMR from dropping too low over time.

How Muscle Mass Directly Impacts BMR

One of the most effective ways to increase your basal metabolic rate is by building lean muscle mass. Muscle tissue is metabolically active — meaning it burns calories at rest.

Research from the Journal of Clinical Investigation shows that 1 lb of muscle burns approximately 6–10 calories per day at rest, while fat tissue burns only 2–3 (Wolfe, 2006).

This makes resistance training a critical part of any metabolism-boosting protocol. Compound movements such as squats, deadlifts, and rows can stimulate large muscle groups, increasing caloric burn both during and after training.

RELATED ARTICLE: 5 Proven Benefits Of Compound Movements

The Role of Hormones in Metabolic Regulation

Your metabolism isn’t just controlled by calories — it’s deeply influenced by hormones. These hormonal signals can raise or lower your metabolic rate, depending on internal and external stimuli.

Key hormones include:

• Thyroid hormones (T3 and T4) – regulate resting metabolic rate

• Leptin and ghrelin – regulate hunger, satiety, and energy expenditure

• Insulin – governs blood sugar and fat storage

• Cortisol – chronic stress can slow metabolism and encourage fat storage

Dysfunction in thyroid hormone output can reduce metabolic rate by up to 30%, according to a review in Endocrine Reviews (Larsen et al., 2011).

This reinforces the importance of managing stress, recovery, and sleep hygiene — not just food and exercise.

Sleep, Hydration, and Your Metabolism

Believe it or not, one night of poor sleep can significantly affect your metabolic efficiency the next day.

A study in the Journal of Clinical Endocrinology & Metabolism found that sleep deprivation reduces RMR by up to 20% (Spaeth et al., 2015).

Sleep also plays a crucial role in:

• Regulating insulin sensitivity

• Managing hunger hormones

• Promoting muscle recovery

Staying well-hydrated is equally important, as even mild dehydration can slow metabolic function. Try drinking a glass of cold water upon waking and before each meal to support digestion and thermogenesis.

RELATED ARTICLE: 10 Proven Tips For Better Recovery And Performance

How Aging Affects BMR — And What To Do About It

With age, your body naturally loses muscle mass — a process known as sarcopenia — which can lower your basal metabolic rate. After age 30, adults lose 3–8% of muscle mass per decade, unless actively strength training.

Fortunately, the decline can be reversed or minimized through:

• Progressive resistance training

• Consistent protein intake (1g per pound of bodyweight)

• Supplements like creatine to preserve lean mass and DHEA which regulates hormones and declines naturally with age.

A 2021 study in Nutrients found that older adults supplementing with creatine showed improved muscle function and increased lean body mass (Candow et al., 2021).

RELATED ARTICLE: How To Build Muscle After 40

Optimizing Your Metabolic Blueprint

Metabolism isn’t static — it’s dynamic and responsive to how you train, eat, sleep, and recover. While your BMR provides the baseline, you can actively shape your metabolic output through consistent lifestyle choices.

If you’re unsure where to start, working with a certified nutrition coach can take the guesswork out of calculating macros, managing energy intake, and designing a program aligned with your goals.

RELATED SERVICE: 1:1 Nutrition Coaching with The Swole Kitchen

How To Calculate Your Basal Metabolic Rate?

You can use our BMR or basal metabolic rate calculator, to find out how many calories you burn each day, so you can have a baseline in order to achieve your goals.

If you love math, you can also calculate your own RMR using the Harris and Benedict (H&B) equation, with the formula below.  

MEN: 88.362 + (13.397 × weight in kg) + (4.799 × height in cm) – (5.677 × age in years)

WOMEN: 447.593 + (9.247 × weight in kg) + (3.098 × height in cm) – (4.330 × age in years)

How To Change Your Basal Metabolic Rate

Your metabolic rate is determined by several factors, some of which you have direct control over, and others which you do not. Those factors include

• Age
• Sex
• Weight
• Height
• Ethnicity
• Body composition
• Genetics

If you want to change your metabolic rate, you have to change your weight and body composition. This, of course, is achieved through your diet, nutrition, and exercise regimen. The more lean muscle mass you have, the more calories your body will burn at rest.

Meeting your health and fitness goals starts and ends in the kitchen, with your nutrition. If you want to reach your goals effectively and fast, then you need to optimize your diet accordingly. Lowering your caloric intake is crucial to burning body fat and achieving your weight loss goals, just as raising your caloric intake is necessary for gaining more mass. If you don’t know where to start, then check out our one-on-one performance-driven nutrition coaching at The Swole Kitchen.

RELATED ARTICLE 8 Natural Ways To Boost Your Metabolism

Another way to boost your metabolic rate is by incorporating a proven thermogenic or weight loss supplement. Fat burners don't work on their own, however, when you pair them with diet and exercise, they can provide a pretty good boost to your metabolic rate. Weight loss ingredients such as green tea extract, and forskolin, are proven to increase fat oxidation through a process called lipolysis. When you workout, your body utilizes more oxygen, which essentially oxidizes, and releases fat cells to be used as fuel. Research has shown that Green Tea Extract, increases fat oxidation by 17-20%.

RELATED ARTICLE Does Green Tea Help Weight Loss?

A fat burner supplement that contains, clinically proven weight loss ingredients such as THERM can improve metabolism and change your metabolic rate. 

RELATED ARTICLE How To Lose Body Fat And Gain Lean Muscle Mass

What Is Basal Metabolic Rate (BMR): Takeaway

If you take your health and fitness seriously, then it's important to know your basal metabolic rate and how many calories you're burning at rest. Your BMR will provide a baseline to help you achieve your body composition goals. 

Looking for a way to improve and boost your metabolism?

Swolverine's Therm® is a natural thermogenic, designed specifically to help you burn more calories at rest and finally reach the body goals you’ve been working for. With 20 clinically proven, active weight loss ingredients such as Green Tea Leaf, Yerba Mate, Garcinia Cambogia, Guarana, and Forskolin, THERM is the perfect weight loss supplement to jumpstart your metabolism, burn more body fat, and boost your energy so you can enhance the results of your fitness journey.

SWOLVERINE is an endurance athlete and active lifestyle brand. Made for the elite athlete, and the strong-willed our products were designed to fuel your athletic performance. We perform when you perform. 

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