Weir Energy Expenditure

Estimate calorimetric energy expenditure with the abbreviated Weir equation.

Description

Indirect-calorimetry models estimate energy expenditure from oxygen consumption and carbon-dioxide production.

Indirect-calorimetry models estimate energy expenditure from oxygen consumption and carbon-dioxide production. This abbreviated Weir calculation omits the urinary-nitrogen term.^{[1, 2]}

Estimate calorimetric energy expenditure with the abbreviated Weir equation.

When to use Weir Energy Expenditure

Use this tool to estimate calorimetric energy expenditure with the abbreviated Weir equation.

Prepare the measured profile, formula counts, upstream model outputs or caller-defined reference criteria requested. Keep paired entries aligned and units, sample basis and preprocessing consistent.

How to use Weir Energy Expenditure and understand its results

Prepare the measured profile, formula counts, upstream model outputs or caller-defined reference criteria requested. Keep paired entries aligned and units, sample basis and preprocessing consistent.
Enter oxygenLitersPerMinute, carbonDioxideLitersPerMinute using the field table and calculation rules, then run the tool.
Read kcalPerMinute, kcalPerHour. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
oxygenLitersPerMinute	Oxygen liters per minute	number	Required
carbonDioxideLitersPerMinute	Carbon dioxide liters per minute	number	Required

Enter nonnegative gas volumes in liters per minute measured on a comparable basis. Return energy estimates per minute and hour.

kcal/min=3.941 VO2+1.106 VCO2; kcal/hour=60×kcal/min

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
kcalPerMinute	Kcal per minute	number
kcalPerHour	Kcal per hour	number

json

{
  "input": {
    "oxygenLitersPerMinute": 1,
    "carbonDioxideLitersPerMinute": 1
  },
  "output": {
    "kcalPerMinute": 5.047,
    "kcalPerHour": 302.82
  }
}

Limitations and assumptions

No gas measurement, calibration or physiological assessment is performed. Steady-state assumptions and suitability of the abbreviated equation require separate evaluation.

Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.

Alternative or Complementary methods

Use Respiratory Exchange Ratio: Classify respiratory exchange ratio against caller-provided fuel bands. For a complementary task, use Cell Normalized OCR: Normalize oxygen consumption to a caller-selected cell count.

Further background: New methods for calculating metabolic rate with special reference to protein metabolism.

References

Weir Energy Expenditure — tool.io
New methods for calculating metabolic rate with special reference to protein metabolism — The Physiological Society

Similar or alternative tools

Respiratory Exchange Ratio
Classify respiratory exchange ratio against caller-provided fuel bands.
Cell Normalized OCR
Normalize oxygen consumption to a caller-selected cell count.