Yes, You Do: How to Add Active Energy to Resting Energy for Total Daily Expenditure

Resting energy accounts for 60% to 75% of the total calories burned each day, powering essential functions like breathing and circulation. However, this baseline is only one part of the equation, leaving many people unsure how to account for the calories burned during exercise and daily movement.

Quick Summary

This guide explains the difference between active and resting energy and confirms that you add them together to calculate your total daily calories burned, also known as your TDEE.

Key Points

• Resting vs. Active Energy: Resting energy (RMR) is what your body burns at rest for basic functions, while active energy is from movement and exercise.

• Calculating Total Daily Energy Expenditure (TDEE): You must add active energy to resting energy to find your TDEE, or total daily calories burned.

• Components of TDEE: TDEE is comprised of RMR, the thermic effect of food, and physical activity (both exercise and non-exercise).

• Importance for Weight Management: To lose, gain, or maintain weight, you must adjust your caloric intake relative to your TDEE.

• Reliable Tracking: Wearable trackers automatically combine resting and active calories, offering a convenient way to monitor your total energy expenditure.

Understanding Resting Energy and Active Energy

To effectively track your calorie burn, it is essential to understand the core components of your daily energy expenditure. The human body burns calories constantly, even at rest. This consumption is for fundamental biological processes, while additional energy is expended through physical activity.

Resting Metabolic Rate (RMR) Explained

Resting Metabolic Rate (RMR), sometimes used interchangeably with Basal Metabolic Rate (BMR), is the energy your body needs to maintain basic physiological functions while completely at rest. This includes keeping your heart beating, lungs breathing, maintaining body temperature, and cell production. Your RMR is influenced by several factors:

• Age
• Gender
• Weight
• Height
• Body composition (muscle mass burns more energy than fat tissue)
• Genetics

While RMR is the largest component of your daily energy burn for most people, it's not the full picture. Your body is not a static machine; it moves and responds to its environment.

The Role of Active Energy

Active energy refers to the calories burned through all physical activity, both structured exercise and non-exercise movement. This includes:

• Exercise Activity Thermogenesis (EAT): Calories burned during intentional workouts like running, lifting weights, or cycling.
• Non-Exercise Activity Thermogenesis (NEAT): Calories burned during everyday movements that are not exercise. Examples include walking around the office, taking the stairs, doing chores, or even fidgeting.
• Thermic Effect of Food (TEF): The energy your body uses to digest, absorb, and metabolize the food you eat.

It is this active energy component that varies the most between individuals and accounts for the difference in daily calorie expenditure for people of the same size and age.

The Calculation: Combining Resting and Active Energy

To get a complete picture of your daily calorie needs, you must combine your resting energy and all forms of active energy. The total is called your Total Daily Energy Expenditure (TDEE).

TDEE = Resting Metabolic Rate (RMR) + Active Energy (EAT + NEAT + TEF)

This is the definitive answer to the question: yes, you add active energy to resting energy. Failing to account for both would lead to a significantly underestimated calorie burn, which is a common error in fitness and weight management. Health apps and wearable trackers use this principle, summing your 'Resting Calories' and 'Active Calories' to display a 'Total' for the day.

How Wearables Track Energy Burn

Wearable devices such as smartwatches and fitness trackers automatically separate and track your energy expenditure. They estimate your resting calories based on personal data like age, gender, height, and weight. They then use motion sensors (like accelerometers) and heart rate monitors to track additional movement, adding those 'active calories' to your resting total. This provides a convenient and relatively accurate estimate of your TDEE without manual calculation.

Comparison: Estimating Total Daily Energy Expenditure

Method	How It Works	Pros	Cons
Mifflin-St Jeor Formula	Calculates BMR using weight, height, age, and sex. Multiplies BMR by an activity factor (e.g., sedentary, lightly active) to estimate TDEE.	Does not require body fat percentage; generally more accurate than older formulas.	Relies on self-reported activity level, which can be inaccurate.
Wearable Tracker	Estimates RMR and measures active energy using sensors (accelerometer, heart rate monitor). Automatically sums daily energy.	Convenient, provides real-time data, and captures daily fluctuations in activity.	Can be less precise, as estimations are based on algorithms and not direct metabolic measurement.
Metabolic Testing	Uses a metabolic cart to directly measure oxygen consumption in a controlled lab setting to determine RMR.	Most accurate method for determining RMR.	Expensive and not practical for daily monitoring.

Manual Calculation: A Practical Approach

For those who do not use a wearable or prefer a manual approach, you can calculate your TDEE using a formula. A popular and accurate method is the Mifflin-St Jeor formula to determine your RMR, which is then multiplied by an activity factor.

Step 1: Calculate your RMR using the Mifflin-St Jeor formula:

• Men: $(10 imes ext{weight in kg}) + (6.25 imes ext{height in cm}) - (5 imes ext{age in years}) + 5$
• Women: $(10 imes ext{weight in kg}) + (6.25 imes ext{height in cm}) - (5 imes ext{age in years}) - 161$

Step 2: Multiply your RMR by an activity factor:

• Sedentary (little to no exercise): RMR x 1.2
• Lightly Active (light exercise 1-3 days/week): RMR x 1.375
• Moderately Active (moderate exercise 3-5 days/week): RMR x 1.55
• Very Active (hard exercise 6-7 days a week): RMR x 1.725
• Extra Active (very hard exercise & physical job): RMR x 1.9

The Importance of TDEE for Your Goals

Knowing your TDEE is fundamental for managing your weight.

• Weight Loss: To lose weight, you must consume fewer calories than your TDEE, creating a calorie deficit.
• Weight Gain: To gain weight, you need to consume more calories than your TDEE.
• Maintenance: To maintain your current weight, you should consume a number of calories equal to your TDEE.

Using this complete calculation, rather than just resting energy alone, gives you a much more realistic target for your daily caloric intake. Understanding this principle empowers you to make informed decisions about your nutrition and fitness regimen.

Conclusion

In short, the answer is a resounding yes: you must add active energy to resting energy to get an accurate measure of your total daily calorie burn. Resting energy, or RMR, is the non-negotiable base level of energy your body needs to survive, while active energy accounts for everything else you do throughout the day, including both structured workouts and incidental movement. Together, they form your Total Daily Energy Expenditure (TDEE), the most crucial figure for understanding your daily calorie needs for weight management. By utilizing accurate formulas or the convenience of wearable technology, you can precisely track your energy balance and achieve your health goals with greater confidence. Learn more about the components of TDEE on the NIH website.

Frequently Asked Questions

Is resting metabolic rate (RMR) the same as active energy?

No, they are distinct. Resting metabolic rate (RMR) is the energy your body burns at rest, while active energy is the energy used for physical movement and exercise. Your total daily energy expenditure is the sum of both.

How do fitness trackers separate resting and active energy?

Fitness trackers estimate your resting calories using your personal data (age, gender, height, weight) to calculate your RMR. They use built-in sensors like accelerometers and heart rate monitors to measure additional movement and attribute those calories to your active energy.

If I only track my active energy, will my calorie count be accurate?

No, it will be highly inaccurate. Active energy is only a fraction of your total daily burn. Your resting energy accounts for the majority of calories burned each day for basic survival functions.

How can I calculate my TDEE manually?

To calculate your TDEE manually, you can use a formula like the Mifflin-St Jeor to estimate your RMR. Then, you multiply your RMR by an activity factor that corresponds to your lifestyle.

What is the best way to determine my total daily energy needs?

The most accurate way is to use a metabolic test, but the most practical method is to calculate your TDEE using an online calculator based on your RMR and activity level or to use a reliable wearable fitness tracker.

Can regular exercise increase my resting energy?

Yes, regular exercise, especially strength training, can increase your resting energy expenditure over time. This is because muscle tissue burns more calories at rest than fat tissue, boosting your RMR.

What role does digestion play in energy expenditure?

The Thermic Effect of Food (TEF) is the energy your body uses to digest and process food. It contributes to your total daily energy expenditure, but it is a relatively small portion compared to RMR and physical activity.