Introduction to Respirometry

What is Respirometry?

Respirometry is the measurement of oxygen uptake rate (VO2) and/or CO2 production rate (VCO2) to monitor energy expenditure and metabolism in living organisms under a variety of conditions, at rest or during activity. Measurements can be made almost anywhere with the right equipment.

The data provide valuable insights into a broad range of physiological and behavioral phenomena.

How is it Measured?

A respirometry system typically includes a chamber in which the sample is accommodated. Learn more about animal respirometry in our recent newsletter.

Simplified respirometry measurement setup
A simplified respirometry measurement setup.


In open systems, the differences in the concentrations of gases entering and leaving the chamber are measured, as is the flow rate of the air moving through the chamber.

Essentially, Exchange Rate = Flow Rate x Differential.


In closed systems, the rate of accumulation of gases is measured in a sealed chamber or with recirculatory gas flow. Gas concentrations are recorded in software and VO2, VCO2, and associated parameters are computed.

Aquatic Respirometry


The same principles apply to aquatic respirometry as to terrestrial respirometry, except that the analyzers usually measure dissolved gas concentrations. Numerous types of dissolved O2 sensors are available. Dissolved CO2 may be measured directly or by monitoring pH. Open flow, intermittent flow, closed flow, and stop flow systems may be used for aquatic respirometry.

Human Respirometry

Q-Track Metabolic Analyzer

There are numerous methods for measuring respirometry in humans. Most require that the subject wears a face mask with O2 being monitored in the inhaled and exhaled breath. Breath flow and volume are also monitored to provide the necessary data for computing VO2 and VCO2. Some human respirometry systems are equivalent to animal systems in which the subject is enclosed in a chamber. Some chambers are room-sized, allowing normal human activities.

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Qubit Intro to Respirometry Summary Sheet
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