Reviewing the current methods of assessing hydration in athletes

Oliver R Barley, Dale W Chapman, Chris R Abbiss, Oliver R Barley, Dale W Chapman, Chris R Abbiss

Abstract

Background: Despite a substantial body of research, no clear best practice guidelines exist for the assessment of hydration in athletes. Body water is stored in and shifted between different sites throughout the body complicating hydration assessment. This review seeks to highlight the unique strengths and limitations of various hydration assessment methods described in the literature as well as providing best practice guidelines.

Main body: There is a plethora of methods that range in validity and reliability, including complicated and invasive methods (i.e. neutron activation analysis and stable isotope dilution), to moderately invasive blood, urine and salivary variables, progressing to non-invasive metrics such as tear osmolality, body mass, bioimpedance analysis, and sensation of thirst. Any single assessment of hydration status is problematic. Instead, the recommended approach is to use a combination, which have complementary strengths, which increase accuracy and validity. If methods such as salivary variables, urine colour, vital signs and sensation of thirst are utilised in isolation, great care must be taken due to their lack of sensitivity, reliability and/or accuracy. Detailed assessments such as neutron activation and stable isotope dilution analysis are highly accurate but expensive, with significant time delays due to data analysis providing little potential for immediate action. While alternative variables such as hormonal and electrolyte concentration, bioimpedance and tear osmolality require further research to determine their validity and reliability before inclusion into any test battery.

Conclusion: To improve best practice additional comprehensive research is required to further the scientific understanding of evaluating hydration status.

Keywords: Dehydration; Fluid; Hydration; Hypohydration; Water balance.

Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Fig. 1
Fig. 1
A flowchart for designing a comprehensive hydration testing protocol

References

    1. Horswill CA, Janas LM. Hydration and health. Am J Lifestyle Med. 2011;5(4):304–315. doi: 10.1177/1559827610392707.
    1. Armstrong LE. Assessing hydration status: the elusive gold standard. J Am Coll Nutr. 2007;26(sup5):575S–584S. doi: 10.1080/07315724.2007.10719661.
    1. Kavouras SA. Assessing hydration status. Curr Opin Clin Nutr Metab Care. 2002;5(5):519–524. doi: 10.1097/00075197-200209000-00010.
    1. Cheuvront SN, Sawka MN. Hydration assessment of athletes. Sports Sci Exchange. 2005;18(2):1–6.
    1. Cheuvront SN, Kenefick RW. Dehydration: physiology, assessment, and performance effects. Compr Physiol. 2014;4:257–85.
    1. Savoie F-A, Kenefick RW, Ely BR, Cheuvront SN, Goulet ED. Effect of Hypohydration on muscle endurance, strength, anaerobic power and capacity and vertical jumping ability: a meta-analysis. Sports Med. 2015;45(8):1207–1227. doi: 10.1007/s40279-015-0349-0.
    1. Barley OR, Chapman DW, Abbiss CR. The current state of weight-cutting in combat sports. Sports. 2019;7(5):123. doi: 10.3390/sports7050123.
    1. Wall BA, Watson G, Peiffer JJ, Abbiss CR, Siegel R, Laursen PB. Current hydration guidelines are erroneous: dehydration does not impair exercise performance in the heat. Br J Sports Med. 2013;bjsports-2013:092417.
    1. James LJ, Funnell MP, James RM, Mears SA. Does hypohydration really impair endurance performance? Methodological considerations for interpreting hydration research. Sports Med. 2019;49:1–12.
    1. Cheuvront SN, Kenefick RW, Montain SJ, Sawka MN. Mechanisms of aerobic performance impairment with heat stress and dehydration. J Appl Physiol. 2010;109(6):1989–1995. doi: 10.1152/japplphysiol.00367.2010.
    1. Barley OR, Chapman DW, Blazevich AJ, Abbiss CR. Acute dehydration impairs endurance without modulating neuromuscular function. Front Physiol. 2018;9:1562. doi: 10.3389/fphys.2018.01562.
    1. Convertino VA, Armstrong LE, Coyle EF, Mack GW, Sawka MN, Senay LC, et al. Exercise and fluid replacement. Med Sci Sports Exerc. 1996;28:377–90.
    1. Zubac D, Marusic U, Karnincic H. Hydration status assessment techniques and their applicability among Olympic combat sports athletes: literature review. Strength Cond J. 2016;38(4):80–89. doi: 10.1519/SSC.0000000000000236.
    1. Armstrong LE, Maughan RJ, Senay LC, Shirreffs SM. Limitations to the use of plasma osmolality as a hydration biomarker. Am J Clin Nutr. 2013;98(2):503–504. doi: 10.3945/ajcn.113.065466.
    1. Barley OR, Iredale F, Chapman DW, Hopper A, Abbiss CR. Repeat effort performance is reduced 24 hours after acute dehydration in mixed martial arts athletes. J Strength Cond Res. 2018;32(9):2555–2561. doi: 10.1519/JSC.0000000000002249.
    1. Greenhalgh T, Thorne S, Malterud K. Time to challenge the spurious hierarchy of systematic over narrative reviews? Eur J Clin Invest. 2018;48(6):e12931. 10.1111/eci.12931.
    1. Sawka MN, Coyle EF. Influence of body water and blood volume on thermoregulation and exercise performance in the heat. Exerc Sport Sci Rev. 1999;27:167–218.
    1. Oppliger RA, Bartok C. Hydration testing of athletes. Sports Med. 2002;32(15):959–971. doi: 10.2165/00007256-200232150-00001.
    1. Fernández-Elías VE, Martínez-Abellán A, López-Gullón JM, Morán-Navarro R, Pallarés JG, De la Cruz-Sánchez E, et al. Validity of hydration non-invasive indices during the weightcutting and official weigh-in for Olympic combat sports. PLoS One. 2014;9(4):e95336. doi: 10.1371/journal.pone.0095336.
    1. Fortes MB, Diment BC, Di Felice U, Gunn AE, Kendall JL, Esmaeelpour M, et al. Tear fluid osmolarity as a potential marker of hydration status. Med Sci Sports Exerc. 2011;43(8):1590–1597. doi: 10.1249/MSS.0b013e31820e7cb6.
    1. Ely BR, Cheuvront SN, Kenefick RW, Sawka MN. Limitations of salivary osmolality as a marker of hydration status. Med Sci Sports Exerc. 2011;43:1080–4.
    1. Shirreffs S. Markers of hydration status. J Sports Med Phys Fitness. 2000;40(1):80.
    1. Sawka MN, Young AJ, Pandolf KB, Dennis RC, Valeri RC. Erythrocyte, plasma, and blood volume of healthy young men. Med Sci Sports Exerc. 1992;24(4):447–453. doi: 10.1249/00005768-199204000-00009.
    1. Dill DB, Costill DL. Calculation of percentage changes in volumes of blood, plasma, and red cells in dehydration. J Appl Physiol. 1974;37(2):247–248. doi: 10.1152/jappl.1974.37.2.247.
    1. Robertson J, Maughan R, Davidson R. Changes in red cell density and related indices in response to distance running. Eur J Appl Physiol Occup Physiol. 1988;57(2):264–269. doi: 10.1007/BF00640674.
    1. Popowski LA, Oppliger RA, Patrick LG, Johnson RF, Kim JA, Gisolf C. Blood and urinary measures of hydration status during progressive acute dehydration. Med Sci Sports Exerc. 2001;33(5):747–753. doi: 10.1097/00005768-200105000-00011.
    1. Sollanek KJ, Kenefick RW, Cheuvront SN, Axtell RS. Potential impact of a 500-mL water bolus and body mass on plasma osmolality dilution. Eur J Appl Physiol. 2011;111(9):1999–2004. doi: 10.1007/s00421-011-1833-3.
    1. Cheuvront SN, Kenefick RW, Charkoudian N, Sawka MN. Physiologic basis for understanding quantitative dehydration assessment. Am J Clin Nutr. 2013;97(3):455–462. doi: 10.3945/ajcn.112.044172.
    1. Hamouti N, Del Coso J, Mora-Rodriguez R. Comparison between blood and urinary fluid balance indices during dehydrating exercise and the subsequent hypohydration when fluid is not restored. Eur J Appl Physiol. 2013;113(3):611–620. doi: 10.1007/s00421-012-2467-9.
    1. Francesconi R, Hubbard R, Szlyk P, Schnakenberg D, Carlson D, Leva N, et al. Urinary and hematologic indexes of hypohydration. J Appl Physiol. 1987;62(3):1271–1276. doi: 10.1152/jappl.1987.62.3.1271.
    1. Armstrong LE, Maresh CM, Castellani JW, Bergeron MF, Kenefick RW, LaGasse KE, et al. Urinary indices of hydration status. Int J Sport Nutr. 1994;4(3):265–279. doi: 10.1123/ijsn.4.3.265.
    1. Nose H, Mack GW, Shi X, Nadel ER. Shift in body fluid compartments after dehydration in humans. J Appl Physiol. 1988;65(1):318–324. doi: 10.1152/jappl.1988.65.1.318.
    1. Gill G, Baylis P, Flear C, Lawson J. Changes in plasma solutes after food. J R Soc Med. 1985;78(12):1009–1013. doi: 10.1177/014107688507801206.
    1. Montain SJ, Cheuvront SN, Carter R. Sawka MN. DTIC Document: Human water and electrolyte balance; 2006.
    1. Chacko B, Peter JV, Patole S, Fleming JJ, Selvakumar R. Electrolytes assessed by point-of-care testing–are the values comparable with results obtained from the central laboratory? Indian J Crit Care Med. 2011;15(1):24. doi: 10.4103/0972-5229.78219.
    1. Edelman I, Leibman J, O'meara M, Birkenfeld L. Interrelations between serum sodium concentration, serum osmolarity and total exchangeable sodium, total exchangeable potassium and total body water. J Clin Invest. 1958;37(9):1236–1256. doi: 10.1172/JCI103712.
    1. Cheuvront SN, Kenefick RW, Sollanek KJ, Ely BR, Sawka MN. Water-deficit equation: systematic analysis and improvement. Am J Clin Nutr. 2012;97(1):79–85. doi: 10.3945/ajcn.112.046839.
    1. Stachenfeld NS, Gleim GW, Zabetakis PM, Nicholas JA. Fluid balance and renal response following dehydrating exercise in well-trained men and women. Eur J Appl Physiol Occup Physiol. 1996;72(5–6):468–477. doi: 10.1007/BF00242277.
    1. Schrier R, Berl T, Anderson R. Osmotic and nonosmotic control of vasopressin release. Am J Physiol Renal Physiol. 1979;236(4):F321–FF32. doi: 10.1152/ajprenal.1979.236.4.F321.
    1. Francesconi R, Sawka MN, Pandolf KB. Hypohydration and heat acclimation: plasma renin and aldosterone during exercise. J Appl Physiol. 1983;55(6):1790–1794. doi: 10.1152/jappl.1983.55.6.1790.
    1. Montain SJ, Laird JE, Latzka WA, Sawka MN. Aldosterone and vasopressin responses in the heat: hydration level and exercise intensity effects. Med Sci Sports Exerc. 1997;29(5):661–668. doi: 10.1097/00005768-199705000-00012.
    1. Hammerum MS, Bie P, Pump B, Johansen LB, Christensen NJ, Norsk P. Vasopressin, angiotensin II and renal responses during water immersion in hydrated humans. J Physiol. 1998;511(1):323–330. doi: 10.1111/j.1469-7793.1998.323bi.x.
    1. Brandenberger G, Candas V, Follenius M, Kahn J. The influence of the initial state of hydration on endocrine responses to exercise in the heat. Eur J Appl Physiol Occup Physiol. 1989;58(6):674–679. doi: 10.1007/BF00418516.
    1. Zerbe R, Miller J, Robertson G. The reproducibility and heritability of individual differences in osmoregulatory function in normal human subjects. J Lab Clin Med. 1991;117(1):51–59.
    1. Ahokoski O, Virtanen A, Kairisto V, Scheinin H, Huupponen R, Irjala K. Biological day-to-day variation and reference change limits of serum cortisol and aldosterone in healthy young men on unrestricted diets. Clin Chem. 1999;45(7):1097–1099. doi: 10.1093/clinchem/45.7.1097.
    1. Ricos C, Arbos M. Quality goals for hormone testing. Ann Clin Biochem. 1990;27(4):353–358. doi: 10.1177/000456329002700412.
    1. Jansen LT, Suh H, Adams J, Sprong CA, Seal AD, Scott DM, et al. Osmotic stimulation of vasopressin acutely impairs glucose regulation: a counterbalanced, crossover trial. Am J Clin Nutr. 2019;110(6):1344–1352. doi: 10.1093/ajcn/nqz236.
    1. Enhörning S, Brunkwall L, Tasevska I, Ericson U, Persson Tholin J, Persson M, et al. Water supplementation reduces copeptin and plasma glucose in adults with high copeptin: the H2O metabolism pilot study. J Clin Endocrinol Metab. 2019;104(6):1917–1925. doi: 10.1210/jc.2018-02195.
    1. Zubac D, Reale R, Karnincic H, Sivric A, Jelaska I. Urine specific gravity as an indicator of dehydration in Olympic combat sport athletes; considerations for research and practice. Eur J Sport Sci. 2018;18(7):920–929. doi: 10.1080/17461391.2018.1468483.
    1. Shirreffs SM, Maughan RJ. Urine osmolality and conductivity as indices of hydration status in athletes in the heat. Med Sci Sports Exerc. 1998;30(11):1598–1602. doi: 10.1097/00005768-199811000-00007.
    1. Sawka MN, Burke LM, Eichner ER, Maughan RJ, Montain SJ, Stachenfeld NS. American College of Sports Medicine position stand. Exercise and fluid replacement. Med Sci Sports Exerc. 2007;39(2):377–390. doi: 10.1249/mss.0b013e31802ca597.
    1. Armstrong LE, Herrera Soto JA, Hacker FT, Jr, Casa DJ, Kavouras SA, Maresh CM. Urinary indices during dehydration, exercise, and rehydration. Int J Sport Nutr. 1998;8(4):345–355. doi: 10.1123/ijsn.8.4.345.
    1. Oppliger RA, Magnes SA, Popowski LA, Gisolfi CV. Accuracy of urine specific gravity and osmolality as indicators of hydration status. Int J Sport Nutr Exerc Metab. 2005;15(3):236–251. doi: 10.1123/ijsnem.15.3.236.
    1. Zubac D, Paravlic A, Reale R, Jelaska I, Morrison SA, Ivancev V. Fluid balance and hydration status in combat sport Olympic athletes: a systematic review with meta-analysis of controlled and uncontrolled studies. Eur J Nutr. 2019;58(2):497–514. doi: 10.1007/s00394-019-01937-2.
    1. Rowat A, Smith L, Graham C, Lyle D, Horsburgh D, Dennis M. A pilot study to assess if urine specific gravity and urine colour charts are useful indicators of dehydration in acute stroke patients. J Adv Nurs. 2011;67(9):1976–1983. doi: 10.1111/j.1365-2648.2011.05645.x.
    1. Freedman SB, Vandermeer B, Milne A, Hartling L, Johnson D, Black K, et al. Diagnosing clinically significant dehydration in children with acute gastroenteritis using noninvasive methods: a meta-analysis. J Pediatr. 2015;166(4):908–16. e6. doi: 10.1016/j.jpeds.2014.12.029.
    1. Armstrong LE, Maresh CM, Gabaree CV, Hoffman JR, Kavouras SA, Kenefick RW, et al. Thermal and circulatory responses during exercise: effects of hypohydration, dehydration, and water intake. J Appl Physiol. 1997;82(6):2028–2035. doi: 10.1152/jappl.1997.82.6.2028.
    1. Zubac D, Cular D, Marusic U. Reliability of urinary dehydration markers among elite youth boxers. Int J Sports Physiol Perform. 2017;13:374–81.
    1. Cheuvront SN, Kenefick RW, Zambraski EJ. Spot urine concentrations should not be used for hydration assessment: a methodology review. Int J Sport Nutr Exerc Metab. 2015;25(3):293–297. doi: 10.1123/ijsnem.2014-0138.
    1. Hew-Butler T, Weisz K. The hydration sweet spot: importance of Aquaporins. Clin Lab Sci. 2016;29(3):186–193. doi: 10.29074/ascls.29.3.186.
    1. Oliver SJ, Laing SJ, Wilson S, Bilzon JL, Walsh NP. Saliva indices track hypohydration during 48 h of fluid restriction or combined fluid and energy restriction. Arch Oral Biol. 2008;53(10):975–980. doi: 10.1016/j.archoralbio.2008.05.002.
    1. Walsh NP, Laing SJ, Oliver SJ, Montague JC, Walters R, Bilzon JL. Saliva parameters as potential indices of hydration status during acute dehydration. Med Sci Sports Exerc. 2004;36(9):1535–1542. doi: 10.1249/01.MSS.0000139797.26760.06.
    1. Walsh NP, Montague JC, Callow N, Rowlands AV. Saliva flow rate, total protein concentration and osmolality as potential markers of whole body hydration status during progressive acute dehydration in humans. Arch Oral Biol. 2004;49(2):149–154. doi: 10.1016/j.archoralbio.2003.08.001.
    1. Cheuvront SN, Ely BR, Kenefick RW, Sawka MN. Biological variation and diagnostic accuracy of dehydration assessment markers. Am J Clin Nutr. 2010;92(3):565–573. doi: 10.3945/ajcn.2010.29490.
    1. Ben-Aryeh H, Roll N, Lahav M, Dlin R, Hanne-Paparo N, Szargel R, et al. Effect of exercise on salivary composition and cortisol in serum and saliva in man. J Dent Res. 1989;68(11):1495–1497. doi: 10.1177/00220345890680110501.
    1. Ljungberg G, Ericson T, Ekblom B, Birkhed D. Saliva and marathon running. Scand J Med Sci Sports. 1997;7(4):214–219. doi: 10.1111/j.1600-0838.1997.tb00142.x.
    1. Sollanek KJ, Kenefick RW, Walsh NP, Fortes MB, Esmaeelpour M, Cheuvront SN. Assessment of thermal dehydration using the human eye: what is the potential? J Therm Biol. 2012;37(2):111–117. doi: 10.1016/j.jtherbio.2011.12.006.
    1. Ungaro CT, Reimel AJ, Nuccio RP, Barnes KA, Pahnke MD, Baker LB. Non-invasive estimation of hydration status changes through tear fluid osmolarity during exercise and post-exercise rehydration. Eur J Appl Physiol. 2015;115(5):1165–1175. doi: 10.1007/s00421-015-3099-7.
    1. Holland JJ, Ray M, Irwin C, Skinner TL, Leveritt M, Desbrow B. Tear osmolarity is sensitive to exercise-induced fluid loss but is not associated with common hydration measures in a field setting. J Sports Sci. 2018;36(11):1220–1227. doi: 10.1080/02640414.2017.1365157.
    1. Owen JA, Fortes MB, Rahman SU, Jibani M, Walsh NP, Oliver SJ. Hydration marker diagnostic accuracy to identify mild intracellular and extracellular dehydration. Int J Sport Nutr Exerc Metab. 2019;29(6):604–611. doi: 10.1123/ijsnem.2019-0022.
    1. Duren DL, Sherwood RJ, Czerwinski SA, Lee M, Choh AC, Siervogel RM, et al. Body composition methods: comparisons and interpretation. J Diabetes Sci Technol. 2008;2(6):1139–1146. doi: 10.1177/193229680800200623.
    1. Schoeller D, Van Santen E, Peterson D, Dietz W, Jaspan J, Klein P. Total body water measurement in humans with 18O and 2H labeled water. Am J Clin Nutr. 1980;33(12):2686–2693. doi: 10.1093/ajcn/33.12.2686.
    1. Lukaski HC, Johnson PE. A simple, inexpensive method of determining total body water using a tracer dose of D2O and infrared absorption of biological fluids. Am J Clin Nutr. 1985;41(2):363–370. doi: 10.1093/ajcn/41.2.363.
    1. Al-Ati T, Preston T, Al-Hooti S, Al-Hamad N, Al-Ghanim J, Al-Khulifi F, et al. Total body water measurement using the 2 H dilution technique for the assessment of body composition of Kuwaiti children. Public Health Nutr. 2015;18(2):259–263. doi: 10.1017/S1368980013003534.
    1. Fields D, Goran MI, McCrory MA. Body-composition assessment via air-displacement plethysmography in adults and children: a review. Am J Clin Nutr. 2002;75(3):453–467. doi: 10.1093/ajcn/75.3.453.
    1. Gerner B, McCallum Z, Sheehan J, Harris C, Wake M. Are general practitioners equipped to detect child overweight/obesity? Survey and audit. J Paediatr Child Health. 2006;42(4):206–211. doi: 10.1111/j.1440-1754.2006.00831.x.
    1. Cheuvront SN, Kenefick RW. CORP: improving the status quo for measuring whole body sweat losses. J Appl Physiol. 2017;123(3):632–636. doi: 10.1152/japplphysiol.00433.2017.
    1. Maughan RJ, Shirreffs SM, Leiper JB. Errors in the estimation of hydration status from changes in body mass. J Sports Sci. 2007;25(7):797–804. doi: 10.1080/02640410600875143.
    1. Leiper JB, Pitsiladis Y, Maughan RJ. Comparison of water turnover rates in men undertaking prolonged cycling exercise and sedentary men. Int J Sports Med. 2001;22(03):181–185. doi: 10.1055/s-2001-15912.
    1. Cheuvront SN, Carter R, III, Montain SJ, Sawka MN. Daily body mass variability and stability in active men undergoing exercise-heat stress. Int J Sport Nutr Exerc Metab. 2004;14(5):532–540. doi: 10.1123/ijsnem.14.5.532.
    1. Montain SJ, Coyle EF. Influence of graded dehydration on hyperthermia and cardiovascular drift during exercise. J Appl Physiol. 1992;73(4):1340–1350. doi: 10.1152/jappl.1992.73.4.1340.
    1. McGee S, Abernethy WB, III, Simel DL. Is this patient hypovolemic? JAMA. 1999;281(11):1022–1029. doi: 10.1001/jama.281.11.1022.
    1. González-Alonso J, Mora-Rodriguez R, Below PR, Coyle EF. Dehydration markedly impairs cardiovascular function in hyperthermic endurance athletes during exercise. J Appl Physiol. 1997;82(4):1229–1236. doi: 10.1152/jappl.1997.82.4.1229.
    1. Cheuvront SN, Ely BR, Kenefick RW, Buller MJ, Charkoudian N, Sawka MN. Hydration assessment using the cardiovascular response to standing. Eur J Appl Physiol. 2012;112(12):4081–4089. doi: 10.1007/s00421-012-2390-0.
    1. Armstrong LE, Ganio MS, Klau JF, Johnson EC, Casa DJ, Maresh CM. Novel hydration assessment techniques employing thirst and a water intake challenge in healthy men. Appl Physiol Nutr Metab. 2014;39(2):138–144. doi: 10.1139/apnm-2012-0369.
    1. Young AJ, Sawka MN, Epstein Y, DeCristofano B, Pandolf KB. Cooling different body surfaces during upper and lower body exercise. J Appl Physiol. 1987;63(3):1218–1223. doi: 10.1152/jappl.1987.63.3.1218.
    1. Greenleaf JE, Morimoto T. Mechanisms controlling fluid ingestion: thirst and drinking. In Buskirk ER, Puhl SM (eds): “Body Fluid Balance: Exercise and Sport.” Boca Raton: CRC Press; 1996.
    1. Ormerod JK, Elliott TA, Scheett TP, VanHeest JL, Armstrong LE, Maresh CM. Drinking behavior and perception of thirst in untrained women during 6 weeks of heat acclimation and outdoor training. Int J Sport Nutr Exerc Metab. 2003;13(1):15–28. doi: 10.1123/ijsnem.13.1.15.
    1. Hubbard RW, Szlyk PC, Armstrong LE. Influence of thirst and fluid palatability on fluid ingestion during exercise. Perspect Exerc Sci Sports Med. 1990;3:39–95.
    1. Going SB, Massett MP, Hall MC, Bare LA, Root PA, Williams DP, et al. Detection of small changes in body composition by dual-energy x-ray absorptiometry. Am J Clin Nutr. 1993;57(6):845–850. doi: 10.1093/ajcn/57.6.845.
    1. Pietrobelli A, Formica C, Wang Z, Heymsfield SB. Dual-energy X-ray absorptiometry body composition model: review of physical concepts. Am J Physiol Endcrinol Metab. 1996;271(6):E941–EE51. doi: 10.1152/ajpendo.1996.271.6.E941.
    1. Baim S, Wilson CR, Lewiecki EM, Luckey MM, Downs RW, Jr, Lentle BC. Precision assessment and radiation safety for dual-energy X-ray absorptiometry: position paper of the International Society for Clinical Densitometry. J Clin Densitom. 2005;8(4):371–378. doi: 10.1385/JCD:8:4:371.
    1. De Lorenzo A, Andreoli A, Matthie J, Withers P. Predicting body cell mass with bioimpedance by using theoretical methods: a technological review. J Appl Physiol. 1997;82(5):1542–1558. doi: 10.1152/jappl.1997.82.5.1542.
    1. Mialich MS, Sicchieri JF, Junior AAJ. Analysis of body composition: a critical review of the use of bioelectrical impedance analysis. Int J Clin Nutr. 2014;2(1):1–10.
    1. Yasumura S, Cohn S, Ellis K. Measurement of extracellular space by total body neutron activation. Am J Physiol Regul Integr Comp Physiol. 1983;244(1):R36–R40. doi: 10.1152/ajpregu.1983.244.1.R36.
    1. Costill D, Cote R, Fink W. Muscle water and electrolytes following varied levels of dehydration in man. J Appl Physiol. 1976;40(1):6–11. doi: 10.1152/jappl.1976.40.1.6.
    1. Ward SR, Lieber RL. Density and hydration of fresh and fixed human skeletal muscle. J Biomech. 2005;38(11):2317–2320. doi: 10.1016/j.jbiomech.2004.10.001.
    1. Graham J, Lamb J, Linton A. Measurement of body water and intracellular electrolytes by means of muscle biopsy. Lancet. 1967;290(7527):1172–1176. doi: 10.1016/S0140-6736(67)91892-2.
    1. Chen L, Kim Y, Santucci KA. Use of ultrasound measurement of the inferior vena cava diameter as an objective tool in the assessment of children with clinical dehydration. Acad Emerg Med. 2007;14(10):841–845. doi: 10.1197/j.aem.2007.06.040.

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