Exercise physiology: oxygen consumption: practice question

A Physiology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Physiology · Exercise physiology: oxygen consumption

Sample item

At maximal exercise, which variable most directly limits further rise in oxygen consumption in a healthy young adult?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

D. Cardiac output

By the Fick principle, oxygen consumption equals cardiac output times arteriovenous oxygen difference. In healthy people, maximal cardiac output is the principal limitation to VO2 max.

Option by option

  • A. Alveolar ventilation alone

    Ventilation increases substantially and is not usually the dominant limitation in healthy subjects.

  • B. Renal blood flow

    Renal blood flow falls during exercise and does not determine maximal oxygen uptake.

  • C. Haemoglobin affinity only

    Haemoglobin unloading adapts but is not the usual central VO2-max limit.

  • D. Cardiac output (correct)

    Correct. Greater cardiac output delivers more oxygen to active muscle.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this Physiology question

What is the answer to this Physiology question?

The best answer is D, Cardiac output. By the Fick principle, oxygen consumption equals cardiac output times arteriovenous oxygen difference.

Why is "Alveolar ventilation alone" not the answer?

Ventilation increases substantially and is not usually the dominant limitation in healthy subjects.

Why is "Renal blood flow" not the answer?

Renal blood flow falls during exercise and does not determine maximal oxygen uptake.

Why is "Haemoglobin affinity only" not the answer?

Haemoglobin unloading adapts but is not the usual central VO2-max limit.

What concept does this question test?

It tests Exercise physiology: oxygen consumption in Physiology. In healthy people, maximal cardiac output is the principal limitation to VO2 max.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Exercise physiology: oxygen consumption?

For each system, sketch the key graph (pressure–volume loop, oxygen dissociation curve, nephron handling) and explain it aloud. Then use the flashcards and the other Physiology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.