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  2. Energy Expenditure Calculator

Energy Expenditure Calculator

Scientific energy expenditure calculator compliant with 2024 international standards. Based on validated research from ACSM, Keytel, Tanaka, and Minetti, our tool offers accuracy comparable to professional wearables.

🔬 Updated in 2024 with the latest Compendium of Physical Activities data and the most recent scientific formulas for optimal estimation of your burned calories.

Personal Information

Activity Parameters

💡 Renseignez distance + durée pour un calcul précis

Advanced Parameters (for greater precision)

Energy Expenditure Results

Activity Duration Distance Elev. Gain Calories
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Activity
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Duration
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Distance
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Elev. Gain
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Calories
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Calculation Methods Used

🎯 Method Priority Order :

  1. Power (Cycling only): Most accurate ±5%
  2. Distance + Time (Running): Specifically calibrated ±10%
  3. Heart Rate: Scientifically validated formula ±10%
  4. MET: Standard method based on activity ±20%

✅ Factors Taken into Account :

  • Male/female metabolic differences
  • Metabolic decline with age
  • Impact of elevation gain on effort
  • Influence of temperature
  • Speed and intensity of effort
  • HR adjustment to refine actual intensity
Important : The results are scientifically based estimates but may vary depending on your individual metabolism (±10-15%). For maximum accuracy: use a power meter (cycling) or provide the distance covered (running).

📚 Scientific Calculator Guide

🎯 Calculation Methods Used

Our calculator uses 4 scientific methods in order of precision:

1️⃣ Mechanical Power (cycling) - Accuracy ±3-5%

Formula: Calories = (Power × Duration × 3600) / (Efficiency × 4184)

Energy efficiency: 24% (male) / 22% (female). The most accurate method as it directly measures mechanical work output.

2️⃣ Distance + Duration (running) - Accuracy ±8-12%

ACSM Formula: VO₂ = (0.2 × speed) + (0.9 × speed × grade%) + 3.5 ml/kg/min

Then conversion: Calories = (VO₂ × Weight / 1000) × 5 × Duration

Reference: ACSM's Guidelines for Exercise Testing (11th ed., 2021)

3️⃣ Heart Rate - Accuracy ±10-15%

Keytel et al. formula (2005):

• Males: [(−55.0969) + (0.6309 × HR) + (0.1988 × Weight) + (0.2017 × Age)] / 4.184 × Duration

• Females: [(−20.4022) + (0.4472 × HR) − (0.1263 × Weight) + (0.074 × Age)] / 4.184 × Duration

Validated on +100 subjects - Journal of Sports Sciences, 2005

4️⃣ Metabolic Equivalent (MET) - Accuracy ±15-25%

Formula: Calories = MET × Weight (kg) × Duration (h)

Reference method based on the Compendium of Physical Activities 2024 (Ainsworth et al.). Used when other data is unavailable.

🏔️ Elevation Calculation (Minetti Polynomial Formula 2002)

Our calculator uses Minetti's complete scientific formula which accounts for both uphill AND downhill:

Formula: C(i) = 155.4×i⁵ − 30.4×i⁴ − 43.3×i³ + 46.3×i² + 19.5×i + 3.6

Where i = gradient (slope as decimal, e.g., 0.10 for 10%) and C(i) = cost in J/(kg·m)

Key points:

  • Uphill: Cost increases exponentially with gradient
  • Downhill: U-shaped cost curve with minimum at −10% (eccentric braking)
  • Steep grades: Significantly higher energy cost

Reference: Minetti et al., Journal of Applied Physiology, 93(3), 1039-1046, 2002

🏞️ Terrain Type Impact

The energy cost of trail running comes from terrain technicality, not the activity itself:

  • Road / Track: Reference (0%)
  • Gravel / Path: +5% (Vernillo et al., 2016)
  • Technical trail: +10% (instability, adaptation)
  • Very technical: +15% (rocks, roots, obstacles)

Important: Trail does NOT have automatic overhead. On identical terrain (flat road), trail = road running.

References: Vernillo et al., Sports Medicine, 2016; Giovanelli et al., IJSPP, 2017

💓 Maximum Heart Rate

Tanaka et al. formula (2001): HRmax = 208 − (0.7 × Age)

This formula replaces the obsolete "220-age" (accuracy ±10 bpm vs ±15 bpm).

Meta-analysis of 18,712 subjects - J Am Coll Cardiol, 2001

📊 MET Values Used (Compendium 2024)

Running & Trail:

  • 8 km/h: 8.3 MET
  • 10 km/h: 10.0 MET
  • 12 km/h: 11.5 MET
  • 14 km/h: 12.8 MET
  • 16 km/h: 15.3 MET

MET automatically adjusts based on your actual speed.

Cycling:

  • <16 km/h: 6.8 MET
  • 16-19 km/h: 8.0 MET
  • 19-22 km/h: 10.0 MET
  • 22-25 km/h: 12.0 MET
  • >25 km/h: 15.8 MET

🌡️ Personal Adjustments

Age: Metabolic decline of −0.5%/year after age 40

Temperature:

  • <0°C: +15% (intense thermoregulation)
  • 0-10°C: +8% (moderate cold)
  • 10-28°C: Comfort zone (no adjustment)
  • 28-35°C: +12% (significant heat)
  • >35°C: +20% (major thermal stress)

💡 Tips to Maximize Accuracy

  • 🚴 Cycling: Use a power meter (±3-5%)
  • 🏃 Running: Provide distance, elevation gain AND loss (±8-12%)
  • 🏔️ Trail: Specify terrain type for accurate calculation
  • 💓 Other sports: Use a heart rate monitor (±10-15%)
  • 📏 Personal data: Provide accurate age, sex, and weight

⚠️ Important note: These calculations are scientific estimates based on population averages. Your individual metabolism, training level, and movement efficiency may cause results to vary by ±10-15%. For precise tracking, we recommend using indirect calorimetry or a power meter.