Resting Metabolic and Respiratory Analysis (PNOE)

Indirect calorimetry test measuring oxygen consumption and carbon dioxide production to assess metabolism, fat utilization, and energy efficiency at rest.

Resting Metabolic and Respiratory Analysis (PNOE)

Table of contents

Basic data

The Resting Metabolic and Respiratory Analysis (PNOE) is a non-invasive test that evaluates your body’s metabolism through precise breath-by-breath gas analysis. It measures oxygen uptake (VO₂) and carbon dioxide output (VCO₂) to determine how efficiently your body converts nutrients into energy at rest.

Using indirect calorimetry, the test calculates resting metabolic rate (RMR), fat versus carbohydrate utilization, and respiratory quotient (RQ). These values provide a detailed understanding of your metabolic flexibility, caloric needs, and overall energy balance — essential data for optimizing nutrition, training, and recovery strategies.

PNOE technology is used worldwide by clinical, sports, and longevity professionals to personalize lifestyle programs based on individual metabolic profiles.

Category: Performance tests

Level: Beginner

Usefulness: High

Level

Beginner

This is a beginner-level performance and metabolic test suitable for anyone interested in understanding their baseline energy metabolism. It provides essential insights for optimizing nutrition, weight management, and energy levels. Ideal as a first step in a personalized longevity or performance plan.

Usefulness

High

The test provides foundational data on how your body produces and utilizes energy, helping tailor dietary and exercise interventions to your specific metabolism.
Personalized nutrition planning

Determines your precise resting caloric expenditure and macronutrient oxidation rates, enabling accurate dietary adjustments for weight control or metabolic optimization.

Assessment of metabolic flexibility

Reveals how effectively your body switches between burning fat and carbohydrates, a key marker of metabolic health and longevity.

Early detection of metabolic inefficiency

Identifies signs of slow metabolism, mitochondrial dysfunction, or low oxygen efficiency before they manifest in clinical biomarkers.

How it works

The PNOE system measures oxygen consumption and carbon dioxide production through a specialized face mask while you rest comfortably. From these gas exchange parameters, it calculates energy expenditure and substrate utilization.
Indirect calorimetry

Measures VO₂ (oxygen intake) and VCO₂ (carbon dioxide output) to assess how much energy your body expends and which fuels (fat or carbohydrates) are being used.

Data processing

The results are analyzed by the PNOE algorithm to determine your resting metabolic rate, respiratory quotient, and fat oxidation efficiency.

Measures

The test provides a detailed view of resting metabolism and substrate use, offering actionable data for nutrition and performance optimization.
Resting Metabolic Rate (RMR)

The number of calories your body burns at rest to maintain vital functions.

Respiratory Quotient (RQ)

Indicates the ratio of fat to carbohydrate oxidation. A value near 0.7 suggests fat-burning, while 1.0 indicates higher carbohydrate utilization.

Fat and Carbohydrate Oxidation

Quantifies the proportion of energy derived from fats vs. carbohydrates at rest.

Oxygen Efficiency (VO₂)

Reflects mitochondrial and cardiorespiratory efficiency during resting conditions.

Reliability

Indirect calorimetry is considered the gold standard for measuring metabolic rate and substrate utilization. PNOE uses FDA-cleared technology validated in both clinical and sports science settings.
Accuracy

Provides highly reproducible results when performed under standardized resting conditions (fasting, controlled temperature, no caffeine or exercise prior).

Device calibration

Each PNOE device undergoes automated calibration before testing to ensure precise gas analysis.

Limitations

While the test accurately measures resting metabolism, results depend on adherence to pre-test conditions and proper calibration.
Sensitive to external factors

Recent exercise, caffeine intake, or inadequate fasting may distort resting metabolic rate readings.

Limited scope

Measures metabolism at rest only; for complete metabolic flexibility assessment, an additional exercise test is recommended.

Frequency

Suggested cadence

Once or twice per year, or after major changes in diet, training, or body composition, to track improvements in metabolic efficiency.

Cost

Typical costs

Approximately €100–200 depending on provider and inclusion of professional interpretation.

Availability

Where available

Available in longevity and performance clinics equipped with PNOE systems.

Preparation

How to prepare

Arrive well-rested, fasted for at least 8–12 hours, and avoid caffeine or intense exercise 24 hours before the test. Breathe normally and remain relaxed throughout the measurement.

Interpretation

The PNOĒ report integrates respiratory, autonomic, and metabolic metrics to assess cellular performance, fuel flexibility, and recovery status. Key areas include: ventilatory efficiency (VE/VCO₂), lung utilization (tidal volume), breathing coordination, autonomic balance and HRV, metabolic rate, metabolic flexibility, and fat oxidation efficiency (mitochondrial function).
Autonomic Balance and HRV

High parasympathetic activity and good HRV indicate low stress load and proper recovery; sympathetic dominance suggests accumulated stress, elevated resting heart rate, and reduced readiness.

Ventilatory Efficiency (VE/VCO₂)

Reflects the lungs’ ability for gas exchange and the “ventilatory cost” per unit of exhaled CO₂. Low scores may suggest airway obstruction, infection, or reduced respiratory efficiency; high efficiency is favorable.

Lung Utilization (Tidal Volume)

Indicates how much of your lung capacity you actually use at rest. Lower values can limit oxygenation and VO₂, and indirectly, overall endurance capacity.

Breathing Coordination

A stable and rhythmic breathing pattern supports CO₂ regulation and autonomic balance; hyperventilation or irregular breathing impairs tissue oxygenation.

Metabolic Rate (RMR/TEE)

Shows whether you burn calories above or below expectations for your age/weight/height. A low rate can hinder weight reduction; a higher one favors efficient energy expenditure.

Fat Oxidation Efficiency and Mitochondria

A high proportion of fat used as fuel at rest indicates good mitochondrial function and lower risk of weight gain; low efficiency suggests carbohydrate dominance and impaired fat oxidation.

Metabolic Flexibility (Fuel Switching)

The ability to quickly switch between fat and carbohydrate utilization depending on feeding or exercise state. Low flexibility is associated with insulin resistance and poorer glycemic control.

Fuel Mix and Caloric Balance

The proportion of fats and carbohydrates used for energy, together with recommended calorie targets for training and rest days, helps calibrate the diet to your goal (fat loss, maintenance, or body composition optimization).

Alternatives

Exercise Metabolic Test (PNOE)

Measures metabolic performance under physical exertion to determine aerobic threshold, VO₂max, and fat-burning zones.

Indirect calorimetry via other systems

Similar metabolic analysis performed with devices like Cosmed or Korr Metacheck, though often less comprehensive than PNOE’s integrated platform.

FAQ

Is the PNOE test safe?

Yes. It is a completely non-invasive procedure using only natural breathing — no radiation or chemical tracers are involved.

Can the test help with weight management?

Absolutely. Knowing your resting metabolic rate allows precise calorie and macronutrient planning to support weight loss or maintenance.

What affects resting metabolism the most?

Muscle mass, sleep quality, thyroid function, and daily activity level are major determinants of metabolic rate and efficiency.