chapter  12
34 Pages

Assessment of Hydration of Athletes

ByFiona E. Pelly, Gary J. Slater, Tanya M. King

Exercise associated with an increase in metabolic rate results in a subsequent rise in body temperature. Increases in skin blood flow and sweat production occur in response

12.1 Introduction ................................................................................................ 341 12.2 Impact of Hypohydration ........................................................................... 342

12.2.1 The Effects of Hypohydration on Thermoregulatory and Cardiovascular Function .............................................................. 342

12.2.2 The Effect of Hypohydration on Exercise Performance .............. 343 12.2.3 Hydration and Health ...................................................................344 12.2.4 Current Drinking Practices of Athletes ....................................... 345

12.3 Assessment of Hydration Status ................................................................. 345 12.3.1 Body Mass Changes .....................................................................348 12.3.2 Urinary Indices ............................................................................ 349

12.3.2.1 Urine Specific Gravity ................................................ 349 12.3.2.2 Urine Osmolality ........................................................ 350 12.3.2.3 Urine Color ................................................................. 350 12.3.2.4 Urine Volume .............................................................. 351 12.3.2.5 Interpretation of Urinary Indices ................................ 351

12.3.3 Hematological Indices ................................................................. 352 12.3.4 Salivary Parameters ..................................................................... 353 12.3.5 Total Body Water Assessment ..................................................... 353

12.4 Assessment of Sweat Rate and Composition ............................................. 354 12.4.1 Sweat Rate Assessment ................................................................ 354 12.4.2 Sweat Composition Assessment ................................................... 358

12.5 Recommendations for Fluid Intake ............................................................ 359 12.5.1 Pre-Exercise Hydration ................................................................360 12.5.2 Fluid Replacement during Exercise .............................................360 12.5.3 Postexercise Fluid Replacement................................................... 362

12.6 Conclusions and Future Directions ............................................................364 12.7 Practical Recommendations ....................................................................... 365 References ..............................................................................................................366