Stressful military training: endocrine reactivity, performance, and psychological impact.
BACKGROUND
We examined the responsiveness of both cortisol and dehydroepiandrosterone sulfate (DHEAS) to the stress of survival training in military men and evaluated relationships to performance, peritraumatic dissociation, and the subsequent impact of stressful events.


METHODS
Baseline salivary cortisol samples were self-collected by 19 men at 0900 and 1930 in a free-living (FL) environment. DHEAS samples were also collected in a subset of this sample (N = 12). Samples were subsequently taken at similar time points during a stressful captivity (SC) phase of training. Repeated-measures analyses of variance with follow-up paired t-tests examined differences across time and conditions.


RESULTS
Significant increases were observed at both time points (0900 and 1930) from FL to SC in both cortisol (0900: 9.2 +/- 3.4 nmol x L(-1) vs. 18.4 +/- 10.5 nmol x L(-1); 1930: 3.5 +/- 3.0 nmol x L(-1) vs. 27.7 +/- 10.9 nmol x L(-1)) and DHEAS (0900: 1.7 +/- 1.3 ng x ml(-1) vs.6.7 +/- 3.5 ngx ml(-1); 1930: 1.5 0.84 ng x ml(-1) vs. 4.5 +/- 3.0 ng x ml(-1)). Also, overall performance during a high-intensity captivity-related challenge was inversely related to the DHEAS-cortisol ratio; conversely, overall performance during a low-intensity captivity-related challenge was positively related to DHEAS at the 0900 time point during SC. Dissociation was unrelated to endocrine indices measured during SC, while total impact of events was inversely related to percent change in DHEAS from FL to SC.


CONCLUSIONS
Cortisol and DHEAS increase in response to allostatic load, and may relate to human performance during SC as well as PTSD symptoms.
Naval Health Research Center, Dept. 162, P.O. Box 85122, San Diego, CA 92186-5122, USA. marc.taylor@med.navy.mil
Marcus K
MK
Taylor
Kenneth P
KP
Sausen
Eric G
EG
Potterat
Lilianne R
LR
Mujica-Parodi
Jared P
JP
Reis
Amanda E
AE
Markham
Genieleah A
GA
Padilla
Deborah L
DL
Taylor
D000328:Adult; D019314:Dehydroepiandrosterone Sulfate / Q000378:metabolism*; D004493:Education; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D008297:Male; D008889:Military Personnel / Q000523:psychology*; D011597:Psychomotor Performance; D012463:Saliva / Q000378:metabolism*; D013315:Stress, Psychological / Q000378:metabolism*
D019314:Dehydroepiandrosterone Sulfate; D006854:Hydrocortisone