What is the difference between resting energy and active energy?

November 20, 2025 •

6 min read

Resting energy, also known as basal metabolic rate (BMR), accounts for 50-80% of your total daily energy expenditure, representing the majority of the calories you burn each day. Understanding the fundamental difference between resting energy and active energy is crucial for anyone interested in weight management, fitness, or metabolic health.

Quick Summary

Resting energy powers the body's basic functions like breathing and circulation, while active energy is the fuel for all physical movement and exercise. The sum of these two, along with the thermic effect of food, equals your total daily energy expenditure.

Key Points

Resting energy (RMR/BMR) is your passive burn: This is the energy your body uses to maintain vital functions while at complete rest, accounting for the majority of your daily calorie expenditure.
Active energy (AEE) is your movement burn: This is the variable portion of your daily calorie burn that comes from all forms of physical activity, from exercise to everyday movements.
Body composition significantly impacts RMR: Individuals with more muscle mass have a higher resting energy expenditure because muscle burns more calories at rest than fat.
Physical activity is highly controllable: You can increase your active energy burn directly through exercise and by consciously increasing non-exercise activity thermogenesis (NEAT) throughout the day.
Combine both for best results: For sustainable weight management, it is most effective to increase your active energy through exercise while also boosting your resting energy by building muscle mass through strength training.
Age and other factors influence RMR: Your resting metabolic rate can be affected by age, gender, body size, and genetics, though some of these factors are less modifiable than activity levels.
Understand your total energy expenditure: Total daily energy expenditure (TDEE) is the sum of resting energy, active energy, and the thermic effect of food, giving you the complete picture of your daily calorie needs.

Understanding the Basics of Energy Expenditure

Your body is constantly burning energy, measured in calories, to sustain life. This total daily energy expenditure (TDEE) is comprised of three main components: resting energy expenditure (REE), the thermic effect of food (TEF), and energy used for physical activity. While TEF accounts for a small portion of your daily burn (around 10% for most people), the distinction between resting and active energy is the most significant factor in managing your weight and fitness.

What is Resting Energy (Resting Metabolic Rate)?

Resting energy, or resting metabolic rate (RMR), is the energy your body expends while at complete rest to maintain vital functions. Think of it as the energy required to simply stay alive—powering your heart, lungs, brain, and other organs as you sleep or sit still. It is similar to basal metabolic rate (BMR), though BMR is typically measured under more strictly controlled conditions.

Several factors influence your RMR:

Body Composition: People with higher muscle mass tend to have a higher RMR because muscle tissue burns more calories at rest than fat tissue.
Age: RMR generally decreases with age, primarily due to a natural loss of muscle mass.
Sex: Men typically have a higher RMR than women, largely due to differences in body composition and a higher average muscle mass.
Body Size: Taller and heavier individuals have a larger surface area and more metabolizing tissue, leading to a higher RMR.
Genetics: Your metabolic rate is partly influenced by genetics.

What is Active Energy (Activity Energy Expenditure)?

Active energy, also known as activity energy expenditure (AEE), is the energy your body burns through all physical movement beyond rest. This includes intentional exercise, such as running or weightlifting, but also encompasses all other daily movements. AEE is the most variable component of your total energy expenditure and is the part you have the most direct control over.

Active energy includes:

Planned Exercise: Deliberate physical activity like jogging, cycling, swimming, or strength training.
Non-Exercise Activity Thermogenesis (NEAT): The energy expended for everything we do that is not sleeping, eating, or sports-like exercise. Examples include walking to the car, fidgeting, doing chores, and standing.
Intensity and Duration: The more intense and longer your physical activity, the more active energy you burn. For example, an hour of running burns significantly more active energy than an hour of watching TV.

Comparison Table: Resting Energy vs. Active Energy


Feature	Resting Energy (RMR/BMR)	Active Energy (AEE)
Function	Energy to power involuntary, vital functions at rest (e.g., breathing, circulation, organ function).	Energy expended through all physical movement and exercise.
Percentage of TDEE	Accounts for the majority (50-80%) of your total daily energy expenditure.	Accounts for the most variable portion, ranging from 15-50% depending on activity level.
Primary Influences	Body composition (muscle vs. fat), age, sex, body size, and genetics.	Intensity, duration, and frequency of physical activity and daily movements.
Control	Less direct control; it can be influenced indirectly by increasing muscle mass through exercise.	High degree of control; determined directly by your level of physical activity.
Impact on Weight	A higher RMR can make it easier to lose or maintain weight.	Increases daily calorie burn, making it easier to create a calorie deficit.
Measurement	Can be estimated using formulas like the Harris-Benedict equation or measured in a lab setting.	Calculated by fitness trackers, smartwatches, and exercise equipment based on intensity and duration.

Why Understanding the Difference Matters

For effective weight management, it is critical to understand both components of your energy burn. Focusing only on active energy can be misleading. While a long run burns a significant amount of calories, your RMR is the engine that runs all day long, even when you're not moving. To boost your total daily calorie expenditure, a combination of strategies is most effective:

Increase your active energy by incorporating more exercise and general movement into your day. Regular physical activity, especially higher-intensity workouts, can also temporarily increase your resting energy expenditure for hours afterward.
Boost your resting energy over the long term by building muscle mass. Strength training exercises, such as weightlifting, help increase lean body mass, which in turn elevates your RMR.
Use fitness trackers wisely. Most fitness trackers calculate your total calories burned by adding your estimated resting calories to your active calories, providing a more complete picture of your energy expenditure.

The Power of Combined Effort

Weight loss and maintenance depend on creating an energy deficit—burning more calories than you consume. This can be achieved by either reducing calorie intake, increasing energy expenditure, or a combination of both. When you focus solely on diet, you risk slowing down your RMR, as the body adapts to conserve energy. By contrast, incorporating regular physical activity helps boost both your active energy burn and, over time, your resting energy burn by building muscle. This dual approach is often more effective and sustainable.

Conclusion

While both resting and active energy are essential parts of your metabolism, they serve different functions. Resting energy is the passive calorie burn that sustains your life, while active energy is the dynamic burn from all physical movement. For optimal health and fitness, it's important to appreciate and influence both. By combining regular exercise to increase your active energy with strategies to build muscle and support your resting energy, you can effectively manage your total daily energy expenditure and achieve your wellness goals.

How to Calculate Your Daily Energy Needs

To calculate your total daily energy expenditure (TDEE), you can first estimate your Resting Metabolic Rate (RMR) and then apply a physical activity factor. There are several equations for this, with the Mifflin-St Jeor equation being a popular choice for its accuracy. After calculating your RMR, you multiply it by an activity multiplier based on your lifestyle.

For example:

Step 1: Calculate RMR. Using a formula, such as the one from the Harris-Benedict method, you can estimate your resting calorie needs.
Step 2: Apply Activity Factor. Multiply your RMR by a factor that corresponds to your average activity level. For example, sedentary (little to no exercise) is typically 1.2, while very active (hard exercise 6-7 days a week) can be up to 1.9.
Step 3: Add TEF. While a small portion, adding the thermic effect of food (approx. 10%) provides a more accurate picture of total daily burn.

This provides a science-backed estimate for creating a calorie deficit or surplus, depending on your goals.

Here is an in-depth guide on calculating your metabolic rate from the National Academy of Sports Medicine.

How to Increase Your Total Energy Burn

Incorporate strength training: Building muscle mass is one of the most effective ways to increase your resting energy expenditure. Muscle tissue is more metabolically active than fat tissue, meaning it burns more calories at rest.
Increase NEAT: Look for small opportunities to move more throughout your day. Take the stairs instead of the elevator, stand up and stretch regularly, or walk during phone calls. These small efforts add up.
Add cardio intervals: High-intensity interval training (HIIT) can increase your RMR for several hours after your workout is over, a phenomenon known as Excess Post-exercise Oxygen Consumption (EPOC).
Fuel properly: While not directly increasing RMR in a major way, eating enough protein can contribute to a higher thermic effect of food. The body uses more energy to digest protein than it does to digest fats or carbohydrates.
Prioritize sleep: Adequate sleep is crucial for regulating hormones that control appetite and metabolism. Poor sleep can disrupt metabolic function and impact energy levels.

Key Takeaways for Balancing Energy

Both resting and active energy are vital for metabolic health and weight management. By understanding how each component works, you can make informed decisions about your diet and exercise habits. Combining consistent physical activity with strategies to preserve and build muscle mass provides a powerful and sustainable way to optimize your overall energy expenditure and achieve your fitness goals.

Note: While fitness trackers and calculators can provide estimates, a professional and personalized assessment by a healthcare provider or registered dietitian is recommended for the most accurate results.

Frequently Asked Questions

Resting energy (RMR) can be estimated with formulas like the Harris-Benedict equation using your age, weight, height, and sex, or measured more precisely in a laboratory with indirect calorimetry. Active energy is estimated by fitness trackers and calculators that measure the intensity and duration of your physical movement.

Yes. Regular physical activity, particularly strength training that builds muscle mass, can increase your resting metabolic rate over time. Muscle tissue is more metabolically active than fat, so building more muscle raises the number of calories your body burns at rest.

Both are important. While active energy provides a direct and immediate calorie burn, resting energy accounts for the majority of your daily expenditure. A holistic approach that addresses both—increasing active energy through exercise and raising resting energy by building muscle—is most effective for sustained weight management.

The thermic effect of food (TEF) is the energy your body uses to digest, absorb, and metabolize the food you eat. It accounts for a smaller percentage of your total daily energy expenditure compared to resting and active energy.

Your resting metabolic rate typically decreases with age due to a natural loss of lean muscle mass. This process can be slowed by staying active and incorporating regular strength training into your fitness routine.

Yes, genetics can play a role in determining your baseline metabolic rate. However, lifestyle factors like body composition and physical activity level have a much greater impact and can be influenced by your choices.

Yes, resting energy expenditure (REE) accounts for the calories burned during sleep and other times of inactivity. It covers the cost of all the body's unconscious physiological processes.