A literature review of recovery and cortisol among military personnel

Introduction Recovery is an essential factor in having a natural resistance to stress. When the body is exposed to a physiological or psychological stressor, a stress reaction occurs, and cortisol is released. This can affect the body in the short and long term. Militaries often practice in realistic scenarios to build resistance to stress and have the conditions to cope with actual events. During the exercises, the military is exposed to both physiological and psychological stress for long periods. After exercises, the body needs to recover to rebuild. Recovery is, therefore, an essential factor for the body. However, there is a research gap for long-term extreme exposure to stress in relation to recovery. The purpose of this study was to review the documentation on the relationship between cortisol levels, stress, and recovery for military personnel. Materials and Methods A general literature study with a descriptive approach was carried out. Cortisol measured from serum, blood plasma, and saliva was included. Only full-text, peer-reviewed papers found in databases from the last 25 years were used. Diagnoses, drug use, or other issues affecting cortisol secretion were excluded. Four databases were searched, and nine relevant quantitative articles were found. A quantitative content analysis was done, and a descriptive result was generated. Results In the literature study, it became apparent that cortisol levels both increase and decrease in professionals in the military when they are exposed to extreme field exercises with insufficient recovery, causing cortisol levels not to return to their basal levels. The analysis of the included articles gave answers to three questions about the role of recovery in a military context. One study was found where cortisol levels and the recovery period differed between women and men. After field training and a 72-hour recovery period, the men's cortisol levels were back to basal levels, while the women's cortisol levels remained elevated for over two weeks. The Conclusion The literature review shows the lack of data on the impact of recovery for military personnel. A study containing both women and men in a group setting was found. Results show significantly longer recovery for women, making it an important research gap. As secrecy is often used in the military context, not all information is published. This affects the quality of the studies and the possibility for high transferability and validity. A longitudinal approach with a larger sample size and additional females should be considered in future studies for comparable results. In addition, more measurement points and a systematization would be desirable with cortisols natural deviations taken into account.