Physical fitness influences stress reactions to extreme military training

Mil Med. 2008 Aug;173(8):738-42. doi: 10.7205/milmed.173.8.738.


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.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adaptation, Psychological*
  • Adult
  • Anxiety / diagnosis*
  • Anxiety / psychology
  • Exercise / psychology*
  • Humans
  • Male
  • Military Medicine*
  • Military Personnel*
  • Physical Fitness*
  • Psychometrics
  • Risk Assessment
  • Risk Factors
  • Stress, Psychological / complications
  • Stress, Psychological / psychology*
  • Time Factors
  • United States