European Journal of Applied Physiology

, Volume 115, Issue 5, pp 1067–1074

Markers of the hydration process during fluid volume modification in women with habitual high or low daily fluid intakes

  • Evan C. Johnson
  • Colleen X. Muñoz
  • Laurent Le Bellego
  • Alexis Klein
  • Douglas J. Casa
  • Carl M. Maresh
  • Lawrence E. Armstrong
Original Article

DOI: 10.1007/s00421-014-3088-2

Cite this article as:
Johnson, E.C., Muñoz, C.X., Le Bellego, L. et al. Eur J Appl Physiol (2015) 115: 1067. doi:10.1007/s00421-014-3088-2



Human daily total water intake (TWI) has a large inter-individual range. Recently, water supplementation has been suggested as a potential preventative and therapeutic modality. Thus, we aimed to measure hydration biomarkers in women with high (HIGH) versus low (LOW) daily TWI to determine baseline differences, and the efficacy of these markers during a systematic alteration in TWI.


This cohort study identified 14 HIGH [3.34 (0.56) L day−1] and 14 LOW [1.62 (0.48) L day−1] from 120 women. Next, fluid intake was decreased in HIGH [2.00 (0.21) L day−1] while LOW increased [3.50 (0.13) L day−1] across 4 days. Body mass, fluid intake, serum osmolality (Sosmo), total plasma protein (TPP), 24 h urine osmolality, and 24 h urine volume, were measured on each day of modified TWI. Estimated plasma volume (Epv) was calculated using measured body mass and hematocrit values.


At baseline, urinary markers and TPP differentiated HIGH from LOW [7.0 (0.3) versus 7.3 (0.3) mg dL−1, respectively]. Upon TWI intervention, (1) body mass decreased in HIGH [−0.7 (1.1) kg, p = 0.010)] but did not increase in LOW [+0.0 (0.6) kg, p = 0.110], (2) Epv decreased 2.1 (2.4)  %, p = 0.004, (3) urine osmolality increased in HIGH [397 (144)–605 (230) mOsm kg−1, p < 0.001] and decreased in LOW [726 (248)–265 (97) mOsm kg−1p < 0.001], and (4) no changes of serum osmolality occurred in either HIGH or LOW (all p > 0.05).


Urinary markers and TPP are sensitive measures to habitual high and low TWI and to changes in TWI. Both groups through urinary and some hematological responses following TWI manipulation achieved regulation of hemoconcentration.


Hydration indices Fluid intake Osmolality Hydration status Fluid regulation 



Estimated plasma volume


Hematocrit (%)


Participant group that habitually consumed 3.34 (0.56) L day−1


Participant group that habitually consumed 1.62 (0.48) L day−1

Serum Cl

Serum chloride (mmol L−1)

Serum K+

Serum potassium (mmol L−1)

Serum Na+

Serum sodium (mmol L−1)


Serum osmolality (mOsm kg−1)


Total plasma protein (mg dL−1)


Total water intake including water from food and beverages


Urine color


Urine osmolality (mOsm kg-1)


Urine specific gravity


Volume of urine produced in 24 h urine collection (L)

Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  • Evan C. Johnson
    • 1
    • 2
  • Colleen X. Muñoz
    • 1
  • Laurent Le Bellego
    • 3
  • Alexis Klein
    • 3
  • Douglas J. Casa
    • 2
  • Carl M. Maresh
    • 2
    • 4
  • Lawrence E. Armstrong
    • 2
  1. 1.Department of Health, Human Performance, and RecreationUniversity of ArkansasFayettevilleUSA
  2. 2.Department of KinesiologyUniversity of ConnecticutStorrsUSA
  3. 3.Hydration and Health DepartmentDANONE ResearchPalaiseauFrance
  4. 4.Department of Human SciencesOhio State UniversityColumbusUSA

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