GLOSSARY

Metabolic Byproduct is a process-associated product, not necessarily useless.

Carbon dioxide, water and heat are normal outputs of metabolism, not a group of toxins. Exhaled carbon dioxide reflects oxidation of different fuels as well as buffering processes; its amount alone is not the amount of body fat lost. Metabolic water contributes to water balance but does not replace fluid intake, and body warmth without a measurement method cannot provide an exact calorie value.

Respiratory quotient relates metabolic carbon dioxide production to oxygen use; respiratory exchange ratio measures the corresponding external gas exchange. They can approximate each other at steady state, but ventilation and buffering during hard exercise separate them. A high value is not automatically an exact carbohydrate percentage. Nonprotein calculations correct protein contribution under defined assumptions. Identify measurement level and conditions rather than treating every breathing ratio as a precise intracellular fuel measurement in all situations.

Mitochondrial respiration passes carrier electrons through a chain to oxygen as final acceptor, forming water and supporting a gradient. Oxygen use and ATP output are related without an immutable ratio. Whole-body oxygen consumption is not exclusively working-muscle metabolism. Distinguish cellular, tissue and respiratory measurements. A higher oxygen-use value can reflect greater demand rather than automatically greater efficiency, and the test context determines what capacity or function can be inferred.