Date of Graduation

5-2015

Document Type

Thesis

Degree Name

Master of Science in Kinesiology (MS)

Degree Level

Graduate

Department

Health, Human Performance and Recreation

Advisor/Mentor

Ganio, Matthew S.

Committee Member

McDermott, Brendon P.

Second Committee Member

Elbin, Robert J.

Keywords

Psychology; Health and environmental sciences; Dehydration; Heat stress; Hydration; Neurocognitive; Obesity; Symptoms

Abstract

INTRODUCTION: Information regarding effects of hypohydration (HY) and hyperthermia (HT) on cognition, mood and development of symptoms is conflicting since the two conditions often confound each other. Further, although obese individuals may have physiological impairments during heat stress, whether psychological impairments occur with HY and HT is unknown. PURPOSE: To assess the independent and combined effects of mild HY and HT on cognition, mood, and the development of symptoms in obese and non-obese females. METHODS: Twenty-two healthy females (11 non-obese, 22±2y, 61±6kg, 25±4% body fat; 11 obese, 22±2y, 80±18kg, 44±5% body fat) volunteered in two randomized, repeated-measures trials, involving passive heating. 24-h prior to heat stress, females either remained euhydrated (EU) or became HY via fluid restriction. EU individuals received fluid during heating to maintain euhydration. Percent BM change and blood osmolality along with urine osmolality and specific gravity were measured prior to and after heating. Cognition (ImPACT, VAS, NASA-TLX), mood (Brunel Mood Scale; BRUMS), and symptoms (visual analog scales) were measured before and after a 1.0ºC increase in core temperature (TC). RESULTS: Participants started the trials within the designated cut-offs for EU and HY. All HY hydration biomarkers were significantly greater than EU at baseline and when hyperthermic (p0.05). HY at baseline impaired Visual Memory and increased temporal demand, frustration, feelings of Depression, and Total Symptom Score (p0.05). HT, while remaining EU, impaired Visual Memory and mental task load and led to negative symptoms and mood (p0.05). However, participants reported increased temporal demand, Anger, and negative symptoms (p0.05). CONCLUSION: These data indicate that HY and HT independently impair Visual Memory, mental task load, and result in development of negative symptoms. HY did not exacerbate the effects of HT on cognition, but greater impairments to mental task load and mood and development of negative symptoms did occur. Body composition does not have an effect on cognition, mood, or the development of negative symptoms with mild HY, mild HT, or when the stressors are combined.

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