For example, one of the most common methods used to determine how much fats and how many carbohydrates you use for energy is a measurement called respiratory exchange ratio (RER), which measures the ratio of carbon dioxide produced to oxygen consumed. (bengreenfieldfitness.com)
Researchers in anther study found that a commercial supplement containing 30 mg of vitamin B6 helped elevate respiratory exchange ratio — a measure of how much fat is burned for energy as opposed to carbs [2]. (instantknockout.com)
Determinants of the variability in respiratory exchange ratio at rest and during exercise in trained athletes. (metabolicefficiency.org)