title: Physical fitness influences stress reactions to extreme military training.
abstract: BACKGROUND
  Physical fitness and physical conditioning have long been valued by the military for their roles in enhancing mission-specific performance and reducing risk of injury in the warfighter. It is not known whether physical fitness plays a causal role in attenuating acute military stress reactions or the evolution of post-traumatic stress disorder.
  
  
  OBJECTIVE
  The objective of this study was to determine whether physical fitness influences the impact of stressful events during military survival training in 31 men.
  
  
  METHODS
  Participants self-reported their most recent Physical Readiness Test scores and completed a trait anxiety measure before survival training. Participants also completed the Impact of Events Scale (IES) 24 hours after training.
  
  
  RESULTS
  Aerobic fitness was inversely associated with the total IES score (p < 0.01, adjusted R2 = 0.19). When adjusted for trait anxiety, this relationship was substantially attenuated and no longer significant (p = 0.11). Trait anxiety was inversely associated with aerobic fitness (p < 0.05) and positively related to IES (p < 0.001).
  
  
  CONCLUSIONS
  Physical fitness may buffer stress symptoms secondary to extreme military stress and its effects may be mediated via fitness-related attenuations in trait anxiety.
authors.affiliation: Stress Physiology Research Core, Department 162, Warfighter Performance, Naval Health Research Center, San Diego, CA 92106, USA. marc.taylor@med.navy.mil
authors.forename: Marcus K
authors.initials: MK
authors.lastname: Taylor
authors.forename: Amanda E
authors.initials: AE
authors.lastname: Markham
authors.forename: Jared P
authors.initials: JP
authors.lastname: Reis
authors.forename: Genieleah A
authors.initials: GA
authors.lastname: Padilla
authors.forename: Eric G
authors.initials: EG
authors.lastname: Potterat
authors.forename: Sean P A
authors.initials: SP
authors.lastname: Drummond
authors.forename: Lilianne R
authors.initials: LR
authors.lastname: Mujica-Parodi