Date of Completion

5-8-2014

Embargo Period

5-8-2014

Keywords

Stress, Exercise, Heat, Dehydration, Immune, cytokine, HSP70, NFAT5, HSF1, eHSP70

Major Advisor

Carl M. Maresh, PhD

Associate Advisor

Elaine C. Lee, PhD

Associate Advisor

Jeff S. Volek, PhD

Associate Advisor

William J. Kraemer, PhD

Associate Advisor

Lawrence E. Armstrong, PhD

Field of Study

Kinesiology

Degree

Doctor of Philosophy

Open Access

Open Access

Abstract

Background: Global changes in immune cells and circulating molecules might indicate whole body stress magnitude. Heat shock protein 70kD (HSP70) and plasma HSP70 might protect through different mechanisms. HSP70 transcription factors, Heat Shock Factor 1 (HSF1) and Nuclear Factor of Activated T-cells 5 (NFAT5) respond to heat and dehydration stress, respectively, and might quantify specific stress exposures. Purpose: Characterize circulating and cellular markers indicating cytoprotective responses following acute stress and recovery in humans. Methods: Laboratory: 36 healthy males completed: 1) "Baseline" followed by 16h fluid deprivation, 2) "Pre" and "Post" 2h cycling (~38°C, ~40%RH), 3) partial rehydration measured "Post1h", 4) and complete recovery ("Recov") upon 24h. Peripheral Blood Mononuclear Cells (PBMCs) were measured for HSP70, HSF1, and NFAT5, and plasma HSP70. Field: 22 healthy males at the 2012 Ironman World Championship. Analyses included Complete Blood Count (CBC) with differential, plasma cytokines, and plasma HSP70 at "Base", "Post", "Post1d", and "Post2d". Athletes who lost least (n=8; Euhy) and most (n=8; Dehy) body mass during the race examined dehydration influences in all variables. Results: Laboratory: PBMCs expressed greater HSP70 at all time points above Base, and at Recov above Pre (pPost2d; p=0.002). More neutrophils (L; p=0.018; %; p=0.030) and nearly less lymphocytes (%; p=0.063) were observed in Dehy than Euhy. Greater IL-10, IL-6 and IL-8 existed at Post than all time points (pConclusion: Whole body stress stimulated an acute inflammatory state in PBMCs and circulating markers. Cellular versus plasma HSP70 exhibited distinct responses, and NFAT5 might indicate whole body dehydration. Understanding cellular mediators might permit greater stress expsure resistance.

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