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PubMed1979

[Effect of long-term work in hot microclimate on various physiological parameters in metallurgists].

The study was carried out in 20 per cent of the total number of workers repairing furnaces. Thermal load of workers exceeded the permissible values of heat stress indices (HSI, P4SR, WBGT). Body temperature and pulse rate in workers, taken at the workplaces, confirmed the high thermal load. In the laboratory there were measured: VO2 max., VC, FEV1 blood pressure (RR) and hemoglobin level (Hb). It was stated that VO2 max. in the consecutive class intervals of age decreased not because of work in heat stress but due to ageing. VO2 max. amounted, in those aged 56--60, to 68 per cent, in comparison with those aged 18--25 years. VD, FEV4 and RR were within the physiological limits. Hb level was lower in all age groups as compared to physiological values. The analysis of workers' age structure indicated that only those with high physical capacity and acclimatization abilities were able to remain in the occupation and reach pensionable age (60 years). The work in heat stress itself causes natural selection of workers. On the basis of the study it was concluded that the pensionable age for workers exposed to heat stress should be lowered.

Acclimatization↗
PubMed1977

Effects of environmental heart on performance and some physiological responses of a man during a psychomotor task.

In climatic chamber experiments some physiological responses of a young healthy man were studied. He was able to perform a pursuitmeter task in a fairly wide range of warm climates without decrement of performance. The highly trained and heat-acclimatized subject was exposed nearly undressed to various ambient temperatures (28--55 degrees C) and air humidities (10--92%) which were combined in such a way that the conditions were tolerable up to 4 h. In 18 experiments the man was sitting quietly all the time, and in a parallel series of 19 experiments (up to 50 degrees C) he performed the pursuitmeter task during the last 2 hours of each exposure. Under equal climatic conditions work caused a slight increase in oxygen uptake corresponding to an increase in metabolic heat generation by about 70 kj/h (17kcal/h) on the average. Rectal temperature and temperature next to the eardrum were 0.1--0.2 degrees C higher at work as compared with rest. Weight loss at work exceeded weight loss at rest, the difference ocrresponding to an increase in evaporative heat loss by about 110 kj/h (26 kcal/h) which resulted in a decrease of mean skin temperature of 0.5 to 0.9 degrees C. Superelevation of heart rate due to work reached about 10 beats/min in a thermally neutral environment, but up to 30 beats/min in hot dry and warm humid surrounding, reflecting the additional effort for maintaining performance under conditions of increasing heat stress.

Acclimatization↗
PubMed1984

[Blood circulation in healthy inhabitants of the arid zone of Turkmenistan. Report 2. Use of controlled exercise test in persons with good and insufficient adaptation to high environmental temperature].

Bicycle ergometry was performed in 143 normal male residents of Ashkhabad in different seasons of the year. In cool weather, the direction and magnitude of hemodynamic response to exercise in Ashkhabad residents were similar to those of people from milder climatic zones. In summer, exercise-related systolic and diastolic blood pressure and the stroke index were smaller as compared to the respective values of the cool season. During the transition period (i.e. first hot summer days), blood pressure and the stroke index were the lowest, and the heart rate was somewhat increased. In hot weather, exercise produced a greater reduction in the circulating blood volume and a greater increase in the hematocrit value. Thirteen (9%) subjects with poor tolerance of hot weather were identified in the screened population. In these, hemodynamic shifts were similar to those observed in most normal subjects during inadequate acclimatization of the first hot summer days.

Acclimatization↗
PubMedDate not supplied

[The respiratory center in normal subjects at 2,240 meters above sea level. The ventilatory and occlusion pressure (P 0.1) responses upon CO2 stimulation].

Altitude hypoxia imposes acute changes and long term adjustments in the ventilation of human beings. Most of the present knowledge of the respiratory center behavior at high altitude derives from the studies of ventilatory response to both hypoxia and hypercapnea. Other indexes of respiratory center output such as the occlusion pressure (P 0.1) response to a variety of stimuli are at present being evaluated. We could not find, however, studies on the P 0.1 responses to CO2 at high altitude. In this study we analyze the ventilatory and P 0.1 responses to CO2 in a group of 32 normal subjects, all of them natives and residents of Mexico city (altitude of 2,240 meters) and we compared them with those reported at sea level. The slope of both, the ventilatory and P 0.1 responses to CO2 was found to be similar to that reported at sea level; 4.52 +/- 1.29 L. min. mmHg and 0.07 +/- 0.01 cm H2O/mmHg respectively. The crossing over of such responses, however, is shifted to the left of the reported at sea level. This means higher levels of both ventilation and P 0.1, for the same level of end-tidal PCO2, at high altitude. This finding might be explained in the basis of the so-called "acclimatization to hypocapnea".

Acclimatization↗
PubMedDate not supplied

Alpine travel. Mountain sickness, the unwelcome companion.

A personal observation and two cases from the literature are described to draw attention to the dangers of mountain sickness and to the rapid progression from the milder form, termed acute mountain sickness, to the more serious conditions of high-altitude pulmonary or cerebral oedema and their possible fatal outcome. The pathogenesis and treatment of the disorders are briefly reviewed. It is stressed that there are no substitutes for acclimatization through gradual ascent and that the best treatment is to descend to a lower altitude.

Acclimatization↗
PubMed1984

[Effect of cold adaptation on the feeding behavior of genetically obese Zucker rats].

A diurnal hyperphagia is certainly the main factor of adiposity in the genetically obese Zucker fa/fa rat. In a previous experiment it was observed that cold-acclimatization suppressed hyperphagia and stopped the increase in obesity. In this work, the chronology of modification in the feeding pattern is studied during the first month of cold exposure (10 degrees C). The main cold-induced modifications are observed after 2 weeks of cold exposure. Possibly the decrease in metabolic efficiency of food could parallel the cold-induced enhancement of energetic capacity of brown adipose tissue which has been described elsewhere. This tissue could play a role in the obesity of the Zucker rat.

Acclimatization↗
PubMedDate not supplied

[CO2 mass transfer and acid-base balance under conditions of muscular activity at sea level and in the mountains].

The state of the blood acid-base balance and dynamics of carbonic acid gas mass transfer were studied in sportsmen at the sea level and in mountains. It is shown that at the sea level due to an intensive muscular activity large amounts of CO2 are formed and excreted; the mass transfer of this gas is multiply accelerated, simultaneously, a pronounced decompensated metabolic acidosis is observed which in some cases is complicated respiratory acidosis. The similar exercises in mountains are followed by a more pronounced disturbance in the acid-base balance and a more intensified mass-transfer of CO2. After 12-day acclimatization and training in mountains the buffer blood capacity increases, the metabolic acidosis under conditions of muscular activity is less pronounced.

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PubMed1981

[Survival in heat (author's transl)].

The clinical characteristics of heat effect are presented in detail, the significance of risk factors emphasized. The demands on an optimal system for treatment of heat are discussed. Medical measures include cooling, treatment for shock, supply of water and salt, controlling acidosis, treatment of coagulation disorders. Preventive measures are acclimatization, hygienic measures in working surroundings, clothing and diet.

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PubMed1981

The relationship between body temperature and intraocular pressure.

A comparison of the intraocular pressures of well-hydrated nonacclimatized and acclimatized subjects during submaximal work load in a hot environment was made. This comparison attempts to eliminate all possible influences on IOP, except body temperature. A direct relationship between the IOP and rectal temperature is postulated.

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PubMedDate not supplied

Effect of acute cold exposure on the mobilization of intramuscular glycogen and triglycerides in the rat.

Male Wistar rats, 300-360 g of body weight, were exposed to cold (1 degree) for 3 and 24 h. The levels of glycogen and triglycerides (TG) were estimated in "white" and "red" portions of the quadriceps muscle (FG and POG muscles respectively) in the soleus muscle (SO muscle), and in the heart muscle. It was found that 3 h cold exposure decreased significantly the glycogen level only in the heart muscle and had no effect in the other muscles examined. Exposure to cold for 24 h reduced the glycogen level in FG and FOG muscles, and lowered further the heart glycogen level. No change of glycogen level during cold exposure was observed in SO muscle. The level of TG in each examined muscle was significantly reduced already after 3 h of cold exposure. After 24 h it remained further unchanged in FG and FOG muscles whereas in SO and heart muscles a partial recovery of TG occurred. It is concluded that in warm-acclimatized rats the intramuscular TG play an important role as a local source of free fatty acids during the first period of acute exposure to cold.

Acclimatization↗
PubMed1980

Electrocardiogram made on ascending the Mount Qomolangma from 50 m a. s. l.

In May 1975, one female mountaineer and eight male mountaineers of our country once more climbed onto the highest peak of the world Mount Qomolangma from the north slope. At the same time, we recorded 15 electrocardiograms while they were climbing from 7,600 m to the peak(8,848.13m) through radio-operated electrocardiography. In this report we mainly analyze the characteristics of electrocardiogram of six mountaineers who ascended the peak at the stage from 50 m a. s. l. to over 8,200m a. s. l. The result proves that although obvious changes after reaching an altitude above 8,200 m from the plain region should be those of indexes of heart rates, the QRS axis, Q-TR, Q-T/T-Q, P wave and T wave, there is no T wave diphasic, inverted, flat or abnormal shifting of S-T segment in the electrocardiogram of these outstanding mountaineers. This fully proves that those summit climbers are of excellent constitution and good adaptation ability to hypoxia. This also shows that the people who have been trained and acclimatized under hypoxia conditions (including permanent altitude residents and native lowlanders) can maintain normal physiological functions under ultra-anoxia for quite a long time.

Acclimatization↗
PubMed1980

Altitude and anesthesia.

The author describes the physiological changes that occur and the anesthetic considerations necessary at increased altitudes and under concomitant low barometric pressure levels, pointing out the differences between the acclimatized and the unacclimatized patient. Drawing from the literature and personal experience, the author explores the altered behavior of respiratory gases and anesthetic agents at increased altitudes.

Acclimatization↗
PubMed1978

Maximal oxygen uptake, heat tolerance and rectal temperature.

To determine the relation of rectal temperature (Tre) to Vo2max and heat tolerance, eight untrained, eight trained and five heat acclimated subjects (respective means +/- SE for Vo2max in ml/kg.min of 37.5 +/- 1.6; 55.7 +/- 1.5; and 54.5 +/- 3.2) were tested in 3 conditions: 60 min of exercise at a fixed load of 35 W at room temperature of 23 degrees C; 60 min of exercise at 35% Vo2max also at 23 degrees C, and 3-hr of exercise in heat (40 degrees C DB, 30 degrees C WB). The heat-acclimated group showed the best heat tolerance, while the untrained group showed the poorest responses in heat. Exercise at 35 W resulted in higher heart rates shown by the untrained, compared with the other subjects, while equilibrium Tre were 37.6, 37.9, and 38.2 degrees C, in the heat-acclimated, trained and untrained groups, respectively, with corresponding differences for resting Tre (36.7, 36.9, and 37.1 degrees C). During exercise at 35% Vo2max, the heat-acclimated group showed lower Tre than the trained group despite working at the same relative loads. Tre during exercise at 35 W at 23 degrees C correlated r = -70 with Vo2max and r = 0.80 with Tre during exercise in heat. These results show that Vo2max accounts for only part of the variability which determines the level of Tre in cool conditions with heat acclimatization accounting for the remainder of this relationship.

Acclimatization↗
PubMed1978

Index for the assessment of heat tolerance.

Heat tolerance was assessed by magnitude of strain induced in the body as a whole by heat load. The strain was represented by a combination of relative water loss, relative rise in rectal temperature and relative salt loss, using those critical values of the three factors which cause heat stroke (40.6 degrees C), water depletion heat exhaustion (7% of body weight) and salt depletion heat exhaustion (0.75 g per kg of body weight). As this numerical heat tolerance index is defined as the degree of disturbance induced by heat exposure concerning thermal regulation, water and electrolyte metabolism, the magnitude of the index is inversely proportional to that of heat tolerance. Our studies showed that adaptive changes in heat tolerance of unacclimatized subjects during short-term heat acclimatization could be followed up by this heat tolerance index and that superior heat tolerance of residents in subtropical zone and athletes could by reasonably evaluated by the index. Thus, it might be said that this numerical heat tolerance index is a reliable index for the assessment of heat tolerance.

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PubMed1994

Differences in narrow-band ultraviolet B and broad-spectrum ultraviolet photocarcinogenesis in lightly pigmented hairless mice.

The carcinogenic effect of 4 ultraviolet (UV) sources was studied in lightly pigmented hairless mice. Two narrow-band UV sources, Philips TL01 and Philips TL12 with a Tempax filter, and two broad-spectrum UV sources, Philips TL12 and Bellarium S, were used. Exposure doses were calculated from the CIE erythema action spectrum. Four groups of mice (n = 20) were exposed to a nonerythemogenic dose (low dose), and 4 groups were exposed to an erythemogenic dose (high dose) of each of the 4 UV sources. One group (control) was not irradiated. The mice in the 4 low-dose groups were all exposed to 0.6 basic minimal erythema doses (B-MED) 5 days/week, and all the mice in the high-dose groups to 1.2 B-MED 5 days/week. After 16 weeks of acclimatization, the doses were doubled. Bellarium S and Philips TL12 were equally carcinogenic in the low-dose regimen and the high-dose regimen. Mice exposed to Philips TL12 with a Tempax filter developed tumors significantly earlier compared with Bellarium and Philips TL12. Philips TL01 was more carcinogenic than any of the other UV sources. Equally erythemogenic doses calculated from the CIE erythema action spectrum seem to be more carcinogenic when derived from narrow-band UVB sources than from broad-band UV sources.

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PubMed1994

Magnetic resonance spectroscopy investigations of brown adipose tissue and isolated brown adipocytes.

Brown adipose tissue and collagenase-isolated brown adipocytes were investigated in rats by means of 1H and 13C nuclear magnetic resonance spectroscopy. After chloroform-methanol extraction of brown adipose tissue, proton and natural abundance 13C spectra of the chloroform fraction showed resonances attributable to triglycerides, and were qualitatively similar to those of the corresponding fraction of white adipose tissue. By means of quantitative analysis of 1H spectra, fatty acid unsaturation and polyunsaturation in triglycerides were found to be lower in brown than white adipose tissue; moreover, unsaturation parameters decreased in triglyceride fatty acids of brown adipose tissue upon norepinephrine administration or cold acclimatization of rats, and were affected by the age of donors. The molar percentage of mono- and polyunsaturated C18 fatty acids in triglycerides was determined from 13C spectra and found to change in the early post-natal period. Isolated, agarose-embedded brown adipocytes from 4-day-old rats showed a number of peaks in the carbohydrate region of 1H spectra that were not present in spectra of white adipocytes and almost disappeared in brown fat cells of older animals. These peaks could be restored by insulin exposure. Natural abundance 13C spectra of isolated brown adipocytes were resolved enough to allow unambiguous assignment of resonances to carbons of fatty acids, glycerol, glucose, ethanolamine, and choline. Calculation of the mono- to polyunsaturated fatty acids ratio in the cells was also performed. Nuclear magnetic resonance spectroscopy is a useful tool for the investigation of brown adipose tissue and adipocytes therefrom.

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PubMed1993

Effects of prolonged lack of amplification on speech-recognition performance: preliminary findings.

The purposes of this investigation were two-fold: 1) to prospectively investigate the effect of prolonged lack of binaural amplification in the unaided ears of adults with bilaterally symmetrical sensorineural hearing impairment (BSSHI) fitted monaurally; and, 2) to prospectively investigate the effects of amplification on speech-recognition performance in the aided ears of monaurally and binaurally fitted subjects. Subjects consisted of 19 monaurally aided adults, 28 binaurally aided adults, and 19 control adults. Both ears of the experimental subjects (binaurally and monaurally aided adults) had BSSHI. The speech measures included the W-22 CID suprathreshold speech-recognition test, nonsense syllable test, and speech-perception-in-noise test. Initial testing was done between 6 and 12 weeks following hearing-aid fitting. Retests were performed approximately 1 year following the initial test. The results revealed that the mean aided minus unaided ear score for the nonsense syllable and W-22 tests increased significantly from the initial test to retest, reflecting a slight improvement in speech performance in the aided ear and a slightly greater decrement in the unaided ear. The findings were interpreted with respect to the theories of auditory deprivation and acclimatization.

Acclimatization↗
PubMedDate not supplied

Psychological and psychophysiological factors in prevention and treatment of cold injuries.

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)

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