Table 2

Markers of hydration status for entire cohort (n=318) and subdivided into females and males

VariableCombined mean±SD
mean±SD n=193
mean±SD n=125
Normal range
Serum [Na+] (mmol/L)139.9±2.1 (134–145)139.7±2.0140.1±2.2135–145
Serum [K+] (mmol/L)4.4±0.3 (3.6–6.4)4.4±0.34.4±0.43.5–5
Serum osmolality (mOsmol/kgH2O)280.6±8.7 (261–307)280.8±8.9280.2±8.3275–295
Urine osmolality (mOsmol/kgH2O)682.7±302 (110–1298)671.6±298.2699.7±308.3300–900
Urine specific gravity1.014±0.006 (1.005–1.030)1.014±0.0061.015±0.006*1.005–1.030
Thirst rating (0–10)4.4±1.8 (0–10)4.5±1.84.2±1.9
  • *P<0.05 between females versus males.

  • The normal physiological range for each biochemical variable is listed in the last column.

  • serum [K+], potassium concentration; serum [Na+], sodium concentration.