Efforts to objectively measure resilience in military personnel are gaining momentum, with research focusing on a panel of circulating biomarkers that indicate a soldier’s ability to withstand and recover from stress. A systematic review of available literature identifies cortisol, dehydroepiandrosterone (sulfate) – DHEA(S) – noradrenaline, serotonin, neuropeptide-Y (NPY), and brain-derived neurotrophic factor as key indicators of performance resilience in a military environment.
The research, aimed at identifying the most promising biomarkers for assessing resilience, acknowledges the challenges of objectively quantifying a trait historically assessed through subjective means. Resilience, is defined as the capacity to overcome the negative impacts of stress on military performance, and is believed to be rooted in a biological adaptation to stressors.
Studies suggest that individuals demonstrating a pronounced, yet controlled, biomarker response to acute stress, coupled with a rapid return to baseline levels, exhibit physiological flexibility linked to greater military-specific resilience. This “physiological window” into resilience is provided by the interplay of cortisol, Insulin-like growth factor-1 (IGF-1), NPY, and DHEA(S).
While neuroendocrine, inflammatory, and growth-related biomarkers have all been independently studied in relation to stress adaptation, researchers emphasize that a comprehensive biomarker panel – accounting for balance across these domains – may be superior to relying on a single biomarker. The interplay of these biomarkers is crucial, as they function in stress adaptations associated with both physical and psychological performance.
Current research highlights the require to establish specific thresholds for biomarker changes in relation to acute stressors and the timing of those changes. Determining these relative thresholds is critical for accurately interpreting a “pronounced but controlled biomarker response” and a “quick recovery to baseline.” Real-time physiological monitoring, pending technological advancements, could facilitate early identification of at-risk soldiers and enable targeted interventions to improve military resiliency, according to recent findings.
A growing body of research focuses on changes in circulating biomarker concentrations and their association with performance outcomes, though fewer studies have investigated prediction and intervention strategies. Biomarkers analyzed from blood, saliva, and urine are being used to understand the biological underpinnings of physiological adaptation, injury risk, and resilience during military training.