respirometric

Respirometric refers to respirometry, the measurement of respiration rates by monitoring the exchange of gases, typically oxygen and carbon dioxide, to quantify metabolic activity. In humans and other organisms, respirometry yields variables such as oxygen uptake (VO2), carbon dioxide production (VCO2), and the respiratory quotient (RQ). When used with energy expenditure calculations, VO2 and VCO2 can be converted to caloric rate using established equations.

Respirometry can be open-circuit (flow-through) or closed-circuit. Open-circuit systems draw ambient air through a mouthpiece or hood and measure expired gas; closed-circuit systems recirculate a known gas mixture and detect gas changes. Modern devices, often called metabolic carts or respirometers, integrate oxygen and carbon dioxide sensors, flow controls, and software. Measurements require calibration for gas concentrations, temperature, humidity, and pressure.

Applications span physiology, medicine, and sports science, including assessment of resting metabolic rate, exercise metabolism, and clinical evaluation of pulmonary or nutritional status. In neonatology, respirometry monitors infants; in sports science, it tracks training adaptations. Beyond humans, respirometry is used in ecology to study soil and aquatic respiration, and in microbiology and environmental engineering to assess microbial respiration in cultures, biofilms, or wastewater treatment.

Limitations include sensitivity to environmental conditions, the need for steady-state measurements for some metrics, and the assumption that gas exchange reflects whole-body metabolism. Accurate interpretation depends on proper standardization, calibration, and consideration of factors such as temperature, barometric pressure, and humidity.