Final answer:
The respiratory exchange ratio (RER), also referred to as the respiratory quotient (RQ), measures the ratio of carbon dioxide produced to oxygen consumed during metabolism, with values indicating the type of fuel (carbohydrates, fats, proteins) being metabolized.
Step-by-step explanation:
What Does the Respiratory Exchange Ratio Measure?
The respiratory exchange ratio (RER), also known as the respiratory quotient (RQ), is a measure used to evaluate respiratory metabolism. It specifically calculates the ratio of carbon dioxide production to oxygen consumption during metabolism. This ratio is pivotal because it indicates the type of fuel source being metabolized by the body—whether it be carbohydrates, fats, or proteins. Each of these macronutrients has a distinct RQ value that reflects how much oxygen is used versus how much carbon dioxide is produced during metabolism.
The RQ equation is represented as RQ = Vc / Vo, where RQ stands for respiratory quotient, Vc stands for the volume of carbon dioxide produced, and Vo indicates the volume of oxygen consumed. This quotient is particularly important when comparing the body's metabolism under different conditions or with the intake of various foods. For instance, an RQ close to 1 suggests a carbohydrate-based metabolism, while lower values like 0.7 and 0.8 suggest fat and protein metabolism, respectively.
The respiratory rate, number of breaths per minute, and other respiratory measurements like tidal volume and expiratory reserve volume (ERV), also contribute to understanding an individual's respiratory health but are separate from the RQ.