GLOSSARY

Ion Concentration is ion quantity per solution volume, requiring the ion species, units and fluid compartment to accompany the value.

Concentration is substance per volume, distinct from total body content. Water shifts can raise or lower a value without a proportional change in total element amount. Unit conversion also distinguishes mass from particle quantity; ion charge matters for some units. Interpretation after exercise therefore considers sampling time and fluid status rather than relying solely on the printed laboratory number.

Sodium is mainly the extracellular cation and potassium mainly intracellular; chloride and other anions contribute to charge balance. Selective membranes, transporters and energy expenditure maintain these distributions. Blood concentration does not directly report muscle content. Movement between compartments may occur faster than changes in total stores and can affect a sample even without a corresponding dietary change.

Serum is obtained after clotting; plasma comes from anticoagulated blood. This distinction matters for sampling and some results. Hemolysis, contamination or an unsuitable anticoagulant can distort certain ion values. For follow-up, record specimen type, units and laboratory reference intervals. Do not attribute differences between reports to diet or athletic performance without considering sample quality and collection conditions.