BACKGROUND: Military exercises generate high levels of stress to simulate combat, providing a unique opportunity to examine cognitive and physiologic responses of normal humans to acute stress. METHODS: Cognitive and physiologic markers of stress were evaluated before, during, and after an intense training exercise conducted for 53 hours in the heat. Cognitive performance, mood, physical activity, sleep, body composition, hydration, and saliva cortisol, testosterone, and melatonin were assessed. Volunteers were 31 male U.S. Army officers from an elite unit, aged 31.6 +/- .4 years. RESULTS: Wrist activity monitors documented that soldiers slept only 3.0 +/- .3 hours during the exercise and were active throughout. Volunteers lost 4.1 +/- .2 kg (p < .001) of weight, predominately water (3.1 +/- .3 L) (p < .001). Substantial degradation in cognitive function, assessed with computerized tests, occurred. Vigilance, reaction time, attention, memory, and reasoning were impaired (p < .001). Mood, including vigor (p < .001), fatigue (p < .001), confusion (p < .001), depression (p < .001), and tension (p < .002), assessed by questionnaire, deteriorated. The highest cortisol and testosterone levels were observed before the exercise. CONCLUSIONS: This study quantifies the overwhelmingly adverse impact of multiple stressors on cognitive performance, mood, and physiologic parameters, during a continuous but brief military exercise conducted by highly motivated, well-trained officers.
BACKGROUND: Military exercises generate high levels of stress to simulate combat, providing a unique opportunity to examine cognitive and physiologic responses of normal humans to acute stress. METHODS: Cognitive and physiologic markers of stress were evaluated before, during, and after an intense training exercise conducted for 53 hours in the heat. Cognitive performance, mood, physical activity, sleep, body composition, hydration, and saliva cortisol, testosterone, and melatonin were assessed. Volunteers were 31 male U.S. Army officers from an elite unit, aged 31.6 +/- .4 years. RESULTS: Wrist activity monitors documented that soldiers slept only 3.0 +/- .3 hours during the exercise and were active throughout. Volunteers lost 4.1 +/- .2 kg (p < .001) of weight, predominately water (3.1 +/- .3 L) (p < .001). Substantial degradation in cognitive function, assessed with computerized tests, occurred. Vigilance, reaction time, attention, memory, and reasoning were impaired (p < .001). Mood, including vigor (p < .001), fatigue (p < .001), confusion (p < .001), depression (p < .001), and tension (p < .002), assessed by questionnaire, deteriorated. The highest cortisol and testosterone levels were observed before the exercise. CONCLUSIONS: This study quantifies the overwhelmingly adverse impact of multiple stressors on cognitive performance, mood, and physiologic parameters, during a continuous but brief military exercise conducted by highly motivated, well-trained officers.
Authors: Douglas J Casa; Julie K DeMartini; Michael F Bergeron; Dave Csillan; E Randy Eichner; Rebecca M Lopez; Michael S Ferrara; Kevin C Miller; Francis O'Connor; Michael N Sawka; Susan W Yeargin Journal: J Athl Train Date: 2015-09 Impact factor: 2.860
Authors: Nathaniel F Watson; M Safwan Badr; Gregory Belenky; Donald L Bliwise; Orfeu M Buxton; Daniel Buysse; David F Dinges; James Gangwisch; Michael A Grandner; Clete Kushida; Raman K Malhotra; Jennifer L Martin; Sanjay R Patel; Stuart F Quan; Esra Tasali Journal: J Clin Sleep Med Date: 2015-08-15 Impact factor: 4.062
Authors: Nathaniel F Watson; M Safwan Badr; Gregory Belenky; Donald L Bliwise; Orfeu M Buxton; Daniel Buysse; David F Dinges; James Gangwisch; Michael A Grandner; Clete Kushida; Raman K Malhotra; Jennifer L Martin; Sanjay R Patel; Stuart F Quan; Esra Tasali Journal: Sleep Date: 2015-08-01 Impact factor: 5.849
Authors: Anne M J van den Heuvel; Benjamin J Haberley; David J R Hoyle; Nigel A S Taylor; Rodney J Croft Journal: Eur J Appl Physiol Date: 2017-03-25 Impact factor: 3.078
Authors: Martin P Paulus; Eric G Potterat; Marcus K Taylor; Karl F Van Orden; James Bauman; Nausheen Momen; Genieleah A Padilla; Judith L Swain Journal: Neurosci Biobehav Rev Date: 2009-05-15 Impact factor: 8.989