Introduction/Aim: Heat stress represents the important problem in military services. This study investigates the effects of exertional heat stress on complex cognitive functions. Methods: 40 male soldiers performed exertional heat stress test, of which 10 performed the test of the same intensity in cool environment. Cognitive functions were mesured by computerized battery CANTAB, before and immediately after exertional heat stress test. Results: Exertional heat stress led to impairment of some cognitive functions in unacclimatized group: decrease of accuracy in MTS test (from 92,6±4,2% towards 84,5±6,9%, p<0,05) and PSRs (from 85,0±8,0% towards 77,0±9,6%, p<0,05), while similar decreases were recorded in MTS test in passively acclimatized group (from 92,2±5,5% towards 87,7±5,6%, p<0,05) i.e. in PSRs test in actively acclimatized group (from 83,3±6,3% towards 69,4±5,1%, p<0,05). The reaction time was not affected in any group whatsoever. Discussion and conclusion: Exertional heat stress leads to mild impairment of complex cognitive functions, particularly in domain of accuracy. Physical strain itself, however, does not affect cognitive functions. Relatively resistance to heat stress in zoung soldiers may be contributed to their high aerobic level.
References
1.
Donaldson GC, Keatinge WR, Saunders RD. Cardiovascular responses to heat stress and their adverse consequences in healthy and vulnerable human populations. International Journal of Hyperthermia. 2003;19(3):225–35.
2.
Quindry J, Miller L, McGinnis G, Kliszczewiscz B, Slivka D, Dumke C, et al. Environmental Temperature and Exercise-Induced Blood Oxidative Stress. International Journal of Sport Nutrition and Exercise Metabolism. 2013;23(2):128–36.
3.
Takahashi M, Suzuki K, Matoba H, Sakamoto S, Obara S. Effects of different intensities of endurance exercise on oxidative stress and antioxidant capacity. The Journal of Physical Fitness and Sports Medicine. 2012;1(1):183–9.
4.
Tomporowski PD. Effects of acute bouts of exercise on cognition. Acta Psychologica. 2003;112(3):297–324.
5.
Jovanovic D, Karkalic R, Zeba S, Pavlovic M, Radakovic S. Physiological tolerance to uncompensated heat stress in soldiers: Effects of various types of body cooling systems. Vojnosanitetski pregled. 2014;71(3):259–64.
6.
Jovanovic D, Karkalic R, Tomic L, Velickovic Z, Radakovic S. Efficacy of a novel phase change material for microclimate body cooling. Thermal Science. 2014;18(2):657–65.
7.
Banta GR, Braun DE. Heat strain during at-sea helicopter operations and the effect of passive microclimate cooling. 1997;68:126–31.
8.
Cheung SS, Sleivert GG. Multiple Triggers for Hyperthermic Fatigue and Exhaustion. Exercise and Sport Sciences Reviews. 2004;32(3):100–6.
9.
Nielsen B, Nybo L. Cerebral Changes During Exercise in the Heat. Sports Medicine. 2003;33(1):1–11.
10.
Selkirk GA, McLellan TM. Influence of aerobic fitness and body fatness on tolerance to uncompensable heat stress. Journal of Applied Physiology. 2001;91(5):2055–63.
11.
NEWSHAM KR, SAUNDERS JE, NORDIN ES. Comparison of Rectal and Tympanic Thermometry During Exercise. Southern Medical Journal. 2002;95(8):804–10.
12.
Færevik H, Eidsmo Reinertsen R. Effects of wearing aircrew protective clothing on physiological and cognitive responses under various ambient conditions. Ergonomics. 2003;46(8):780–99.
13.
ISO 9886: Ergonomics evaluation of thermal strain by physiological measurements. 2008;
14.
ISO 12894 (E): Ergonomics of the thermal environment -Medical supervision of individuals exposed to extreme hot or cold environment. 2008;
15.
Radakovic S, Maric J, Rubezic V, Surbatovic M, Radjen S. Effects of acclimation on water and electrolitic disbalance in soldiers during exertional heat stress. Vojnosanitetski pregled. 2007;64(3):199–204.
16.
Radakovic S, Maric J, Surbatovic M, Vasiljevic N, Milivojevic M. Influence of acclimatization on serum enzyme changes in soldiers during exertional heat stress. Vojnosanitetski pregled. 2009;66(5):359–64.
17.
Radakovic SS, Maric J, Surbatovic M, Radjen S, Stefanova E, Stankovic N, et al. Effects of Acclimation on Cognitive Performance in Soldiers during Exertional Heat Stress. Military Medicine. 2007;172(2):133–6.
18.
Cheung SS, McLellan TM. Heat acclimation, aerobic fitness, and hydration effects on tolerance during uncompensable heat stress. Journal of Applied Physiology. 1998;84(5):1731–9.
19.
J. Fray P, W. Robbins T, J. Sahakian B. Neuorpsychiatyric applications of CANTAB. International Journal of Geriatric Psychiatry. 1996;11(4):329–36.
20.
Hancock PA, Vasmatzidis I. Effects of heat stress on cognitive performance: the current state of knowledge. International Journal of Hyperthermia. 2003;19(3):355–72.
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