science

Weir formula

Weir formula is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Weir formula rather than just read about it. In short: The Weir formula is a formula used in indirect calorimetry, relating metabolic rate to oxygen consumption and carbon dioxide production. According to original source, it says: Metabolic rate (kcal per day) = 1.440 (3.9 VO2 + 1.1 VCO2) where VO2 is oxygen consumption in litres per minute and VCO2 is the rate of carbon dioxide production in litres per minute.

Key takeaways

Weir formula belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Weir formula to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Weir formula from memory before moving on to harder problems.

Reference excerpt

The Weir formula is a formula used in indirect calorimetry, relating metabolic rate to oxygen consumption and carbon dioxide production. According to original source, it says:

Metabolic rate (kcal per day) = 1.440 (3.9 VO2 + 1.1 VCO2) where VO2 is oxygen consumption in litres per minute and VCO2 is the rate of carbon dioxide production in litres per minute. The formula can also be written for units of calories per day where VO2 is oxygen consumption expressed in millilitres per minute and VCO2 is the rate of carbon dioxide production in millilitres per minute. Another source gives

Energy (kcal/min) = (respiration in L/min times change in percentage oxygen) / 20 This corresponds to:

Metabolic rate (cal per minute) = 5 (VO2 in mL/min)

References

Further reading Weir, J. B. de V. (1949). "New methods for calculating metabolic rate with special reference to protein metabolism". The Journal of Physiology. 109 (1–2) (published 1 August 1949): 1–9. doi:10.1113/jphysiol.1949.sp004363. PMC 1392602. PMID 15394301.

Worked examples

Example 1 — a first encounter with Weir formula

Start with the simplest possible case. Write down what Weir formula claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Weir formula before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Weir formula ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Weir formula

In research: Weir formula appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Weir formula in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Weir formula is common in secondary-school and first-year university syllabi. It links to neighbouring topics Calorimetry, so understanding it makes those chapters shorter.
In everyday life: Look for Weir formula outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Weir formula in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Weir formula means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Weir formula out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Weir formula in simple terms?

The Weir formula is a formula used in indirect calorimetry, relating metabolic rate to oxygen consumption and carbon dioxide production. According to original source, it says: Metabolic rate (kcal per day) = 1.440 (3.9 VO2 + 1.1 VCO2) where VO2 is oxygen consumption in litres per minute and VCO2 is…

Why does Weir formula matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Weir formula?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Weir formula.