Fluid balance and hydration status in combat sport Olympic athletes: a systematic review with meta-analysis of controlled and uncontrolled studies
- 132 Downloads
Athletes in Olympic combat sports experience body water fluctuations resulting from training and intentional dehydration when making weight. Despite the popularity of urine specific gravity (USG) and urine osmolality (UOSM) measurement in characterizing fluid fluctuations, their utility remains questioned. This systematic review/meta-analysis examined the utility of urinary hydration indices in laboratory and field settings in Olympic combat sport athletes.
27 articles met the inclusion criteria for systematic review, 15 studies were included in the meta-analysis; with USG and UOSM the main outcome variables. Meta-regression analyses evaluated the interrelationship among body mass (BM), fluid intake, and urine measures.
Significant USG alterations were observed following different sampling time frames: dehydration (ES 0.59; 95% CI 0.46–0.72; p = 0.001), follow-up period (ES 0.31; 95% CI 0.11–0.50; p = 0.002) and rehydration (ES − 0.34; 95% CI − 0.56 to − 0.12; p = 0.003). Direct comparison of laboratory (ES 0.20; 95% CI − 0.19 to 0.59; p = 0.324) and field (ES 0.35; 95% CI 0.14–0.56; p = 0.001) sampling showed marginally trivial and small effects. Small effects on UOSM were observed following dehydration (ES 0.31; 95% CI 0.12–0.74, p = 0.15), follow-up period (ES 0.39; 95% CI 0.08–0.70, p = 0.015) and rehydration (ES − 0.45; 95% CI − 0.60 to 0.30, p = 0.001). Meta-regression analysis suggests only fluid intake predicts USG alterations (p = 0.044) during rehydration protocols.
There were likely small changes in both USG and UOSM readings across all experimental conditions, with moderate-to-large heterogeneity in all studies, except for USG readings during dehydration protocols. The meta-regression failed to provide conclusive evidence concerning the interrelationship among urine measures, BM fluctuations, and fluid intake.
KeywordsDehydration, combat sports Thermoregulation Water Systematic review
This research did not receive any grant from funding agencies in the public or commercial sectors.
Compliance with ethical standards
Conflict of interest
Reid Reale is an employee of the Gatorade Sports Science Institute, a division of PepsiCo, Inc.; which is a manufacturer of beverages, sports drinks and hydration products. All other authors certify that they have no affiliations with or involvement in any organization or entity with any financial or non-financial interest in the subject matter or materials discussed in this manuscript.
Damir Zubac, Igor Jelaska, and Vladimir Ivancev are employed by the University of Split, Faculty of Kinesiology, Split, Croatia, EU. Armin H. Paravlic and Damir Zubac are employed by the Science and Research Center Koper, Institute for Kinesiology Research, Koper, Slovenia, EU. Reid Reale is employed by the Gatorade Sports Science Institute, a division of PepsiCo, Inc. Shawnda Morrison is employed by the University of Primorska, Faculty of Health Sciences, Polje 42, 6310 Izola, Slovenia. The views expressed in this article are those of the authors and do not necessarily reflect the position or policy of PepsiCo, Inc.
- 4.Guyton AC, Hall JE (2006) Textbook of medical physiology. Elsevier, PhiladelphiaGoogle Scholar
- 19.Buford TW, Rossi SJ, Smith DB, O’Brien MS, Pickering C (2006) The effect of a competitive wrestling season on body weight, hydration, and muscular performance in collegiate wrestlers. J Strength Cond Res 20(3):689–692Google Scholar
- 25.Gleim GW (2000) In chapter: Renal response to training and exercise: book exercise and sport science: Lippincott Williams & Wilkins, London, pp 221–222Google Scholar
- 29.Maher CG, Sherrington C, Herbert RD, Moseley AM, Elkins M (2003) Reliability of the PEDro scale for rating quality of randomized controlled trials. Phys Ther 83(8):713–721Google Scholar
- 33.Fernandez-Elias VE, Martinez-Abellan A, Lopez-Gullon JM, Moran-Navarro R, Pallares JG, De la Cruz-Sanchez E, Mora-Rodriguez R (2014) Validity of hydration non-invasive indices during the weight-cutting and official weigh-in for Olympic combat sports. PLoSOne 9(4):e95336. https://doi.org/10.1371/journal.pone.0095336 CrossRefGoogle Scholar
- 34.Cochrane Consumers and Communication Group resources for authors (Internet) (2016) p 1. http://cccrg.cochrane.org/author-resources. Accessed 15 Feb 2017
- 40.Pallarés JG, Martínez-Abellán A, López-Gullón JM, Morán-Navarro R, De la Cruz-Sánchez E, Mora-Rodríguez R (2016) Muscle contraction velocity, strength and power output changes following different degrees of hypohydration in competitive Olympic combat sports. J Int Soc Sports Nutr 13(1):10CrossRefGoogle Scholar
- 41.Ratamess NA, Hoffman JR, Kraemer WJ, Ross RE, Tranchina CP, Rashti SL, Kelly NA, Vingren JL, Kang J, Faigenbaum AD (2013) Effects of a competitive wrestling season on body composition, endocrine markers, and anaerobic exercise performance in NCAA collegiate wrestlers. Eur J Appl Physiol 113(5):1157–1168CrossRefGoogle Scholar
- 52.Kutlu M, Demirkan E, Özbek, ME (2015) Assessments of world and national level wrestling teams at a pre-world championship competition: hydration, body composition and body mass alterations. J Sports Med Phys Fitness 55(4):305–312Google Scholar
- 57.Stuempfle KJ, Drury DG (2003) Comparison of 3 methods to assess urine specific gravity in collegiate wrestlers. J Athl Train 38(4):315Google Scholar
- 58.Sommerfield LM, McAnulty SR, McBride JM, Zwetsloot JJ, Austin MD, Mehlhorn JD, Utter AC (2016) Validity of urine specific gravity when compared with plasma osmolality as a measure of hydration status in male and female NCAA collegiate athletes. J Strength Cond Res 30(8):2219–2225CrossRefGoogle Scholar
- 61.Utter AC, McAnulty SR, Riha BF, Pratt BA, Grose JM (2012) The validity of multifrequency bioelectrical impedance measures to detect changes in the hydration status of wrestlers during acute dehydration and rehydration. J Strength Cond Res 26(1):9–15. https://doi.org/10.1519/JSC.0b013e318238ea51 CrossRefGoogle Scholar
- 63.Zubac D, Karnincic H, Zaja M (2016) Hydration status assessment among elite youth amateur boxers. J Sports Med Phys Fitness 56(6):731–736Google Scholar
- 74.Higgins JP, Altman DG, Gøtzsche PC, Jüni P, Moher D, Oxman AD, Savović J, Schulz KF, Weeks L, Sterne JA (2011) The Cochrane Collaboration’s tool for assessing risk of bias in randomized trials. BMJ 343d5928Google Scholar