Combat and blast exposure blunt sympathetic response to acute exercise stress in specialised military men.

Abstract

Electrodermal activity (EDA)-a measure of electrical skin conductance reflecting (exclusive) sympathetic control of the eccrine sweat gland-holds promise as an indicator of central sympathetic activation. The aim of this study was to determine whether combat and blast exposure modulate the EDA response to acute exercise stress in specialised military men. Fifty-one men (age M=36.1, SD=6.5) participated in this study as part of the Explosive Ordnance Disposal Operational Health Surveillance System. The EDA complex (i.e., tonic+phasic conductance) was continuously measured throughout a maximal effort, graded exercise test. As expected, exercise stress resulted in measurable, stepwise increases in EDA before tapering at higher exercise intensities. Individuals with more substantial combat exposure and those with blast exposure demonstrated blunted EDA patterns in comparison to their low/nonexposed counterparts. This blunted pattern might imply sub-optimal sympathetic nervous system function in the exposed cohorts and enhances our knowledge of factors influencing resilience in these men.