EXERCISE-INDUCED DEHYDRATION AND ITS EFFECTS ON MOOD, PERCEPTION, AND SLEEPINESS IN SEDENTARY SUBJECTS

Purpose: To determine 1) the impact of dehydration on perception, mood, and sleepiness and 2) the ability of salivary osmolality to detect hydration status. Method: Four female and 2 male (19-22 yrs) volunteers self-reported casual exercise 3 or less times/week. Acute states of dehydration were generated by requiring hydrated participants to exercise until weight was reduced by 2% of pre-exercise weight. All subjects were hydrated during a 48 hour period before testing by consuming a predetermined volume of water based on their weight. At 6:00 AM on the day of testing food and water intake was stopped. At 7:00- AM pre-exercise perception tasks and mood and sleepiness scales were administered. Immediately upon completion they began their exercise program for 1.5 - 2.5 hrs without fluids. Saliva samples were collected from each subject immediately post-exercise. Perception tasks, and sleepiness and mood scales were re-administered. Saliva samples were obtained one and two hrs after psychological testing. For the hydration phase the above conditions were repeated and subjects hydrated without exercise for 1.5- 2.5 hrs. The following perception tasks and scales were administered: 1) the Autokinetic Illusion, 2) Rod-Frame Task 3) eye alignments 4) Epworth Sleepiness Scale and 5) Positive and Negative Affect Scale.