Fluid and Electrolyte Balance during Indoor Tennis Match Play

.................................................................................................................. 10 Chapter 1: Introduction............................................................................................ 11 Study Aims...................................................................................................... 15 Hypothesis....................................................................................................... 16 Chapter 2: Review of Literature............................................................................... 17 2.1 Thermoregulation and the Sweating Response ......................................... 18 2.2 Sweating Rates, Dehydration & Fluid Intake............................................ 19 2.2.1 The Sweating Rate ........................................................................... 19 2.2.2 Sweat Rates in Sporting Environments ............................................. 20 2.3 Dehydration, its physiological effects and resulting impact upon performance ........................................................................................................ 22 2.3.1 Research on Dehydration: A Brief History ....................................... 23 2.3.2 Effects of Dehydration on the Body.................................................. 24 2.3.4 Hypohydration and Possible Effects on Performance........................ 28 2.3.5 Pre-exercise Hydration Status........................................................... 28 2.3.6 Hyperhydration and Possible Effects on Performance....................... 29 2.3.7 Possible Errors in the Estimation of Hydration Status from Changes in Body Mass....................................................................................................... 29 2.4 Thirst and Fluid Intake............................................................................. 30 2.4.1 Voluntary Dehydration..................................................................... 30 2.4.2 Fluid Replacement, Gastric Emptying, and Carbohydrate-Electrolyte Drinks ......................................................................................................... 32 2.4.3 Hydration Issues in Tennis ............................................................... 35 2.5 Electrolyte Balance .................................................................................. 35 2.5.1 Sweat Electrolyte Content ................................................................ 36 2.5.2 Total Electrolyte Losses ................................................................... 39 2.5.3 Effect of Heat Acclimation on the Sweating Response ..................... 39 2.5.4 Relationship between Sweat Sodium Concentration and Sweat Rate 40 2.5.5 Evidence of Sodium Depletion in Heat Cramps ................................ 41 2.5.6 Hyponatremia................................................................................... 42 2.5.7 Fluid and Electrolyte Replacement ................................................... 43 2.5.8 Dietary Sodium Intake for Athletes and Non-Athletes ...................... 45