Evaluation of Physiological and Psychological Impairment of Human Performance in Cold Stressed Subjects (original) (raw)
Related papers
Experimental physiology, 1998
A study was undertaken in man to investigate whether during moderate cold stress, the proportion of carbohydrate (CHO) oxidized is increased, and whether prior prolonged exhaustive exercise compromises thermoregulation. Eight euglycaemic men were cooled by a liquid-conditioned suit (1) after an overnight fast (Con) and (2) approximately 2 h after an exercise protocol in which CHO availability was substantially lowered (Post-Ex). The cooling stimulus lasted 90 min (Cooling) and was preceded by a 30 min thermo-neutral baseline phase (Base). In Con, aural temperature (T(aural)) and the rate of CHO oxidized (CHOox) were not altered from the values at Base during Cooling, whereas the following were increased: the rate of heat production (Hprod, approximately 1.9-fold), thigh electromyographical activity (EMG, approximately 2.5-fold), and the rate of fat oxidized (FATox, approximately 1.7-fold). In Post-Ex, T(aural) did not decrease from the value at Base during Cooling, and compared with...
Cold Stress Effects on Exposure Tolerance and Exercise Performance
Comprehensive Physiology, 2015
Cold weather can have deleterious effects on health, tolerance, and performance. This paper will review the physiological responses and external factors that impact cold tolerance and physical performance. Tolerance is defined as the ability to withstand cold stress with minimal changes in physiological strain. Physiological and pathophysiological responses to short-term (cold shock) and long-term cold water and air exposure are presented. Factors (habituation, anthropometry, sex, race, and fitness) that influence cold tolerance are also reviewed. The impact of cold exposure on physical performance, especially aerobic performance, has not been thoroughly studied. The few studies that have been done suggest that aerobic performance is degraded in cold environments. Potential physiological mechanisms (decreases in deep body and muscle temperature, cardiovascular, and metabolism) are discussed. Likewise, strength and power are also degraded during cold exposure, primarily through a decline in muscle temperature. The review also discusses the concept of thermoregulatory fatigue, a reduction in the thermal effector responses of shivering and vasoconstriction, as a result of multistressor factors, including exhaustive exercise.
Effects of Cold Air Stress on the Performance of a Command and Control Task
Human Factors, 1996
Performance on a simulated command and control warfare task was examined as a function of cold-air-induced adrenergic stress. Twenty participants who were experienced with naval war fighting systems completed a scripted 54-min scenario task while exposed to room temperatures of either 22°C or 4°C. The combined task and cold-exposure paradigm significantly elevated heart rate and catecholamine levels. Task performance was nearly identical for both groups for the scenario as a whole. During a 12-min portion of the scenario when hostilities were simulated, stressed participants were more liberal with missile fire and more conservative in their responses to commands requiring greater knowledge of the tactical situation. The responses to commands requiring participants to identify symbols with particular attributes were equivalent for both groups during the hostilities phase. The study demonstrates the utility of the task-independent stressor paradigm for the examination of complex task performance under stress.
Human Factors and Ergonomics in Manufacturing & Service Industries, 2018
There is little epidemiological data to make reliable conclusions about the effects of exposure to cold on the body's physiological responses. The current study aimed to address this lacuna in the available research. The study sample consisted of 50 outdoor mechanic workers as a case group and 15 staff members as a control group used in the outdoor automechanic workshops. Air environmental factors, including dry-bulb temperature and air velocity, were measured by the portable hot wire thermo anemometer in the workstation of each subject. The body's physiological responses were also measured during daily activities in accordance with ISO 9886. Using Semmes-Weinstein monofilament, touch sensory tests were conducted for determining hands' sensorineural functions. The baseline measurements showed the mechanic workers had lower finger sensation levels and finger skin temperatures than the control group (p < 0.05). This may be attributed to long-term exposure to acute cold air during cold seasons. However, after short-term exposure to extreme cold environment, the mechanic workers showed lower losses in finger skin temperatures and finger sensation levels than the control group (p < 0.05). The findings confirmed that prolonged localized cold exposure among mechanic workers can result in localized habituation of vasoconstrictor responses.
Physiological characteristics of cold acclimatization in man
International Journal of Biometeorology, 1981
Studies were conducted on 15 healthy young soldiers to evaluate the effect of a cold acclimatization schedule on the thermoregulatory and metabolic activity on exposure to acute cold stress. These men were exposed to cold (10~ for 4 h daily wearing only shorts for 21 days, in a cold chamber. They were subjected to a standard cold test at 10 + I~ the day 1, 6, 11 and 21. The subjects were made to relax in a thermoneutral room (26-28~ for 1 h and their heart rate, blood pressure, oxygen consumption, oral temperature, mean skin temperature, mean body temperature, peripheral temperatures, and shivering activity were recorded. Then they were exposed to 10~ and measurements were repeated at 30 min intervals, for 2 h. The cold induced vasodilatation (CIVD), cold pressor response and thermoregulatory efficiency tests were measured initially and at the end of acclimatization schedule. The data show that the procedure resuited in elevated resting metabolism, less fall in body temperature during acute cold stress, reduction in shivering, improvement in CIVD and thermoregulatory efficiency and less rise in BP. and HR during cold pressor response. The data suggest the possibility of cold acclimatization in man by repeated exposure to moderately severe cold stress.
Autonomic neuroscience : basic & clinical, 2016
Cold exposure in humans causes specific acute and chronic physiological responses. This paper will review both the acute and long-term physiological responses and external factors that impact these physiological responses. Acute physiological responses to cold exposure include cutaneous vasoconstriction and shivering thermogenesis which, respectively, decrease heat loss and increase metabolic heat production. Vasoconstriction is elicited through reflex and local cooling. In combination, vasoconstriction and shivering operate to maintain thermal balance when the body is losing heat. Factors (anthropometry, sex, race, fitness, thermoregulatory fatigue) that influence the acute physiological responses to cold exposure are also reviewed. The physiological responses to chronic cold exposure, also known as cold acclimation/acclimatization, are also presented. Three primary patterns of cold acclimatization have been observed, a) habituation, b) metabolic adjustment, and c) insulative adjus...
Psychological and psychophysiological factors in prevention and treatment of cold injuries
PubMed, 1993
Cold injured patients in Alaska come from many sources. Although sport and work continues to provide large numbers of cold injured, most severe repeat injuries tend to reflect other biopsychosocial consequences. Certain behaviors can increase the probability of injury, however all persons living in cold climates are potential candidates. One can decrease risk by education, knowledge and intelligent behavior. Proper respect for adequate protection and hydration seem to be critical factors. Understanding the psychological, physiological and psychophysiological aspects of the cold environment performer helps refine the prevention and treatment strategies for cold injury. Skill training with bio-behavioral methods, such as thermal biofeedback, and the value of medical psychotherapy appear to offer continued promise by facilitating physiologic recovery from injury, as well as assisting in long term rehabilitation. Both approaches increase the likelihood of a favorable healing response by soliciting active patient participation. Medical Psychotherapy for traumatic injuries can also help identify and manage cognitive emotional issues for families and patients faced with the permanent consequences of severe thermal injuries. Thermal biofeedback therapy has the potential benefit of encouraging greater self-reliance and responsibility for self-regulating overall health by integrating self-management skills regarding physiology, diet and lifestyle. Inpatient and outpatient biofeedback training offers specific influence over vascular responses for healing, as well as providing an effective tool for pain management. Interest in cold region habitation has continued to expand our study of human tolerance to harsh, extreme environments. Biological, psychological, sociological, and anthropological views on adaptation, habituation, acclimatization, and injury in cold environments acknowledges the role of development, learning and educated responses to cold environments. The study of health, performance, and injury prevention in extreme isolated cold environments has important strategic and scientific implications. What is learned from behavioral studies of cold survival provides an opportunity to increase our scientific knowledge and understanding. These cold research findings can assist in our future exploration of cold, underwater farming at great depths, and to far distance space travel to cold planets. The relatively new research frontier "Polar Psychology" has evolved to study how interactions with cold environments can have both positive and/or negative consequences. This research simulates the psychological factors likely to be encountered while exploring isolated cold regions of distant galaxies. The psychological and psychophysiological correlates of cold experience appear to be a function of four interactive issues: the environment, genetic predisposition, learning or experience, and finally perception or cognition. Individual cold tolerance seems to relate heavily on sensation, perception and behavior.(ABSTRACT TRUNCATED AT 400 WORDS)
International Archives of Occupational and Environmental Health, 2012
Purpose Differences among individuals concerning susceptibility to local cold injury following acute cold exposure may be related to function of the autonomic nervous system. We hypothesized that there are differences in heart rate variability (HRV) between individuals with normal or more pronounced vasoconstriction following cold exposure and that there is an adaptation related to prolonged cold exposure in autonomic nervous system response to cold stimuli. Methods Seventy-seven young men performed a cold provocation test, where HRV was recorded during cold hand immersion and recovery. Forty-three subjects were reexamined 15 months later, with many months of cold weather training between the tests. Subjects were analyzed as 'slow' and 'normal' rewarmers according to their thermographic rewarming pattern. Results For the 'pre-training' test, before cold climate exposure, normal rewarmers had higher power for low-frequency (P LF) and high-frequency (P HF) HRV components during the cold provocation test (ANOVA for groups: p = 0.04 and p = 0.005, respectively). There was an approximately 25 % higher P HF at the start in normal rewarmers, in the logarithmic scale. Low frequency-tohigh frequency ratio (P LF /P HF) showed lower levels for normal rewarmers (ANOVA for groups: p = 0.04). During the 'post-training' cold provocation test, both groups lacked the marked increase in heart rate that occurred during cold exposure at the 'pre-training' setting. After cold acclimatization (post-training), normal rewarmers showed lower resting power values for the low-frequency and high-frequency HRV components. After winter training, the slow rewarmers showed reduced low-frequency power for some of the cold provocation measurements but not all (average total P LF , ANOVA p = 0.05), which was not present before winter training. Conclusions These HRV results support the conclusion that cold adaptation occurred in both groups. We conclude that further prospective study is needed to determine whether cold adaptation provides protection to subjects at higher risk for cold injury, that is, slow rewarmers.