Cargando…

Intraocular Pressure Is a Poor Predictor of Hydration Status following Intermittent Exercise in the Heat

Current hydration assessments involve biological fluids that are either compromised in dehydrated individuals or require laboratory equipment, making timely results unfeasible. The eye has been proposed as a potential site to provide a field-based hydration measure. The present study evaluated the e...

Descripción completa

Detalles Bibliográficos
Autores principales: Stewart, Ian B., Dias, Brittany, Borg, David N., Bach, Aaron J. E., Feigl, Beatrix, Costello, Joseph T.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5285388/
https://www.ncbi.nlm.nih.gov/pubmed/28203205
http://dx.doi.org/10.3389/fphys.2017.00036
_version_ 1782503833288572928
author Stewart, Ian B.
Dias, Brittany
Borg, David N.
Bach, Aaron J. E.
Feigl, Beatrix
Costello, Joseph T.
author_facet Stewart, Ian B.
Dias, Brittany
Borg, David N.
Bach, Aaron J. E.
Feigl, Beatrix
Costello, Joseph T.
author_sort Stewart, Ian B.
collection PubMed
description Current hydration assessments involve biological fluids that are either compromised in dehydrated individuals or require laboratory equipment, making timely results unfeasible. The eye has been proposed as a potential site to provide a field-based hydration measure. The present study evaluated the efficacy and sensitivity of intraocular pressure (IOP) to assess hydration status. Twelve healthy males undertook two 150 min walking trials in 40°C 20% relative humidity. One trial matched fluid intake to body mass loss (control, CON) and the other had fluid restricted (dehydrated, DEH). IOP (rebound tonometry) and hydration status (nude body mass and serum osmolality) were determined every 30 min. Body mass and serum osmolality were significantly (p < 0.05) different between trials at all-time points following baseline. Body mass losses reached 2.5 ± 0.2% and serum osmolality 299 ± 5 mOsmol.kg(−1) in DEH. A significant trial by time interaction was observed for IOP (p = 0.042), indicating that over the duration of the trials IOP declined to a greater extent in the DEH compared with the CON trial. Compared with baseline measurements IOP was reduced during DEH (150 min: −2.7 ± 1.9 mm Hg; p < 0.05) but remained stable in CON (150 min: −0.3 ± 2.4 mm Hg). However, using an IOP value of 13.2 mm Hg to predict a 2% body mass loss resulted in only 57% of the data being correctly classified (sensitivity 55% and specificity 57%). The use of ΔIOP (−2.4 mm Hg) marginally improved the predictive ability with 77% of the data correctly classified (sensitivity: 55%; specificity: 81%). The present study provides evidence that the large inter-individual variability in baseline IOP and in the IOP response to progressive dehydration, prevents the use of IOP as an acute single assessment marker of hydration status.
format Online
Article
Text
id pubmed-5285388
institution National Center for Biotechnology Information
language English
publishDate 2017
publisher Frontiers Media S.A.
record_format MEDLINE/PubMed
spelling pubmed-52853882017-02-15 Intraocular Pressure Is a Poor Predictor of Hydration Status following Intermittent Exercise in the Heat Stewart, Ian B. Dias, Brittany Borg, David N. Bach, Aaron J. E. Feigl, Beatrix Costello, Joseph T. Front Physiol Physiology Current hydration assessments involve biological fluids that are either compromised in dehydrated individuals or require laboratory equipment, making timely results unfeasible. The eye has been proposed as a potential site to provide a field-based hydration measure. The present study evaluated the efficacy and sensitivity of intraocular pressure (IOP) to assess hydration status. Twelve healthy males undertook two 150 min walking trials in 40°C 20% relative humidity. One trial matched fluid intake to body mass loss (control, CON) and the other had fluid restricted (dehydrated, DEH). IOP (rebound tonometry) and hydration status (nude body mass and serum osmolality) were determined every 30 min. Body mass and serum osmolality were significantly (p < 0.05) different between trials at all-time points following baseline. Body mass losses reached 2.5 ± 0.2% and serum osmolality 299 ± 5 mOsmol.kg(−1) in DEH. A significant trial by time interaction was observed for IOP (p = 0.042), indicating that over the duration of the trials IOP declined to a greater extent in the DEH compared with the CON trial. Compared with baseline measurements IOP was reduced during DEH (150 min: −2.7 ± 1.9 mm Hg; p < 0.05) but remained stable in CON (150 min: −0.3 ± 2.4 mm Hg). However, using an IOP value of 13.2 mm Hg to predict a 2% body mass loss resulted in only 57% of the data being correctly classified (sensitivity 55% and specificity 57%). The use of ΔIOP (−2.4 mm Hg) marginally improved the predictive ability with 77% of the data correctly classified (sensitivity: 55%; specificity: 81%). The present study provides evidence that the large inter-individual variability in baseline IOP and in the IOP response to progressive dehydration, prevents the use of IOP as an acute single assessment marker of hydration status. Frontiers Media S.A. 2017-02-01 /pmc/articles/PMC5285388/ /pubmed/28203205 http://dx.doi.org/10.3389/fphys.2017.00036 Text en Copyright © 2017 Stewart, Dias, Borg, Bach, Feigl and Costello. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Physiology
Stewart, Ian B.
Dias, Brittany
Borg, David N.
Bach, Aaron J. E.
Feigl, Beatrix
Costello, Joseph T.
Intraocular Pressure Is a Poor Predictor of Hydration Status following Intermittent Exercise in the Heat
title Intraocular Pressure Is a Poor Predictor of Hydration Status following Intermittent Exercise in the Heat
title_full Intraocular Pressure Is a Poor Predictor of Hydration Status following Intermittent Exercise in the Heat
title_fullStr Intraocular Pressure Is a Poor Predictor of Hydration Status following Intermittent Exercise in the Heat
title_full_unstemmed Intraocular Pressure Is a Poor Predictor of Hydration Status following Intermittent Exercise in the Heat
title_short Intraocular Pressure Is a Poor Predictor of Hydration Status following Intermittent Exercise in the Heat
title_sort intraocular pressure is a poor predictor of hydration status following intermittent exercise in the heat
topic Physiology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5285388/
https://www.ncbi.nlm.nih.gov/pubmed/28203205
http://dx.doi.org/10.3389/fphys.2017.00036
work_keys_str_mv AT stewartianb intraocularpressureisapoorpredictorofhydrationstatusfollowingintermittentexerciseintheheat
AT diasbrittany intraocularpressureisapoorpredictorofhydrationstatusfollowingintermittentexerciseintheheat
AT borgdavidn intraocularpressureisapoorpredictorofhydrationstatusfollowingintermittentexerciseintheheat
AT bachaaronje intraocularpressureisapoorpredictorofhydrationstatusfollowingintermittentexerciseintheheat
AT feiglbeatrix intraocularpressureisapoorpredictorofhydrationstatusfollowingintermittentexerciseintheheat
AT costellojosepht intraocularpressureisapoorpredictorofhydrationstatusfollowingintermittentexerciseintheheat