Abstract
Background
The interaction between high physical performance under extreme conditions and the simultaneous control of the cognitive executive functioning has been a subject of research in literature for the past few decades. Stroop test and Heart-rate variability (HRV), have been verified as a valuable clinical tool for the assessment of cerebral and autonomic/ cardiovascular stress responses respectively.
Objective
The investigation of HRV adaptive response to stress and cognitive stress resilience under strenuous conditions.
Methods
34 subjects were enrolled (n = 34). Of them, 18 were candidates under intense preparation for their enlistment in the Hellenic Navy SEALs (H.N.S.) and 16 were healthy controls, matched for sex and similar in age and demographics. All subjects underwent standard Color Word Stroop Testing, arithmetic stroop testing and emotional stroop testing, along with mental state and personality examination with the use of Symptom Checklist 90 Revised (SCL-90R) scl-90 and Eysenck Personality Questionnaire (EPQ), respectively. HRV variables in time and frequency domains recordings were acquired, during each aforementioned cognitive testing procedure.
Results
Our results showed that H.N.S.’s performance on both cognitive and emotion stroop tasks (p ≥ 0.054 for all cognitive and emotion stroop tasks’ features) was equivalent to controls even though they exhibited statistically significant lower levels of HRV in different time (ranged from p < 0.01 to p < 0.05) and frequency domain variables (ranged from p < 0.01 to p < 0.05). Finally, in a between group comparison of the psychometric tools, O.Y.K.s had significantly higher somatization, anxiety and neuroticism than controls.
Conclusion
In conclusion, these findings indicate flexible autonomic regulation (HRV) supports recovery following challenge during cognitive and emotional tasks (stroop tests), which in turn supports problem solving or adaptability skills. HRV measurement begins to be a sophisticated and relevant tool for both scientific and clinical insights, promising to be an index regarding the psychophysiological resilience especially in the neurovisceral integration (NVI) model. However further longitudinal research on the field is required.
Resilience of The Hellenic Navy Seals Assessed by Heart Rate Variability During Cognitive Tasks
