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.
Subject(s)
Military Personnel , Exercise , Exercise Test , Galvanic Skin Response , Humans , Male , Sympathetic Nervous SystemABSTRACT
The first of its kind, this study determined whether blast exposure interacts with genetic variant 5HTTLPR to predict posttraumatic stress (PTS) symptoms in 78 military explosives operators. In all models, blast-exposed 5HTTLPR S carriers registered definitively higher PTS symptoms in comparison to non-exposed S carriers, as well as exposed and non-exposed LL carriers (all p < 0.01). All findings were robust to confounding influences of age and traumatic brain injury diagnosis. Not only is blast exposure prevalent in EOD personnel, but it also interacts with genetic predisposition to predict trauma symptoms in this unique, at-risk military population.
