[Effect of noise, exertion and thermal load on temporary auditory threshold shift (TTS) and on fatigue]. / Wplyw halasu, wysilku fizycznego i obciazenia cieplnego na czasowe podwyzszenie progu sluchu (TTS) i zmeczenie.

Temporary threshold shifts were determined in 14 voluntary subjects who were exposed during one hour to noise levels 70, 85 and 100 dB(A) accompanied by physical exercise (30% VO2max), thermal load (TE = 32.0 +/- 0.8 degrees C), and after combined exposure to these three factors. Before and after each exposure, temporary were measured threshold shifts (TTS2) at frequencies 3, 4 and 6 kHz. The psychophysical fatigue was determined using flicker and blinking tests. The results showed that exposure to noise, noise and thermal load, noise and exercise, and combined noise-exercise -thermal load exposure induced statistically significant increases of TTS values, especially at 85 and 100 dB(A) noise levels. Noise and thermal load, noise and exercise, and the combination of the three did not cause psychophysical fatigue, probably on account of the short duration of exposure. The results of this work show that estimation of exposure to noise, performed by measuring noise levels at workplaces and comparing them with the current standards without considering the effects of exercise and/or thermal load is not sufficient to evaluate occupational exposure and the risk of permanent hearing loss.

Circadian variations in psychophysiological responses to heat exposure and exercise.

Ten healthy men were tested at 0600, 1200, 1800 and 2400 hours on different days at rest in a laboratory at room temperature followed by 1 h of heat exposure in a climatic chamber at 42 degrees C, 60% rh (50 min rest and 10 min exercise on a cycle ergometer at 50% VO2max). Heart rate, blood pressure, rectal temperature Tre, metabolic rate, number connection test, visual and auditory reaction time, flicker test and catecholamine excretion were measured. Heat exposure and exercise caused lower heart rate acceleration at 2400 hours than at 0600 and 1200 hours, the smallest increase of Tre at 1800 hours, and an increase in metabolic rate greater at 1200 than at 1800 hours. In the afternoon, when, according to the circadian rhythm, the body temperature is highest, the additional heat load produced the smallest physiological effects. Performance efficiency, after heat exposure combined with physical exercise, improved slightly, but diurnal variations did not show significant circadian rhythm.

[General physical fitness of metallurgy workers exposed to thermal load]. / Ogólna wydolnosc fizyczna hutników zatrudnionych w warunkach narazenia na obciazenie termiczne.

General physical fitness of 475 metallurgists, 203 subjects working under heat stress and 272 subjects working under normal environment conditions, has been determined. Evaluation of physical fitness was based on the maximal oxygen consumption (VO2max), the Harvard "Step test" and some laboratory examinations. Physical fitness was below average, poor and very poor in both groups without statistically significant differences between the exposed and control groups. A statistically significant correlation has been found between VO2max and Harvard "Step test". Arterial hypertension greater than or equal to 21,3/12,7 kPa has been found in 27% of subjects of the exposed group and in 23% of the control group. Cholesterol level greater than or equal to 6,7 nmol/l has been found in 14,8% of the exposed and in 17,6% of the control group. A statistically significant negative correlation between the cholesterol concentration and the score of the Harvard "Step test" of both groups has been found, and also between VO2max of the exposed group only. Above 50% of subjects exhibited various abnormalities in electrocardiogram mainly of type IV, VII, IX, according to the Minnesota Code. General physical fitness of metallurgists has been considerably lower as compared to the literature data. It is concluded that periodic examinations of general physical fitness should be performed for evaluation of the health condition. Industrial physicians should utilize the results of those examinations for prevention.

Voluntary dehydration in men working in heat.

An investigation was carried out on 77 steelworkers, divided into two groups, at their work places. Group I (30 subjects) drank ad lib. a special tea containing (17.1 mmol/l NaCl, 1.34 mmol/l KCl, 0.14 mmol/l Na2HPO4, and 0.57 mmol/l vitamin C). Group II (47 subjects) drank ad lib. ordinary drinks (water, mineral water, and soda-water). Determination of water balance was performed seven times in all within 3 weeks. In groups I and II sweat losses were 5.1 +/- 1.2 kg and 5.0 +/- 1.3 kg, and intakes were 4.1 +/- 1.1 kg and 3.4 +/- 1.1 kg, respectively. When the intake period of the drinks with salts was extended it was found that voluntary dehydration decreased and amounted to 10% of sweat rate on the last day of the study. The voluntary dehydration in group I was lower by 40%, the difference being highly significant in comparison with group II (P < 0.001). Data obtained from anamnesis and a questionnaire results showed smaller fatigue, higher work capability and better subjective feelings in group I. Five subjects who previously had complained of recurrent pain and muscle spasm experienced disappearance of these symptoms. The importance of intake of water containing salts in hot working conditions and their role in maintaining the water-electrolyte balance for normal physiological functions and subjective feelings were discussed.

[5-Hydroxyindoleacetic acid and creatinine excretion in thermal stress]. / Wydalanie kwasu 5-hydroksyindolooctowego (5-HIOL) i kreatyniny w moczu w stresie cieplnym.

The determination of 5-HIIA and creatinine excretion in thermal stress was performed in two series, in the first (I) on 102 healthy men aged 20--45 yrs (58 smokers and 55 non-smokers) and in the second one (II) on 20 men after drinking of 1 1 water immediately before thermal stress. The subjects remained at rest in the climatic chamber for 90 min in the temperature of 45 +/- 1 degrees C and relative humidity of 70 +/- 5 per cent. Thermal stress resulted in a significant increment of body temperature after 45 min and after consecutive 45 min of exposure, and lack of steady state. Creatinine and 5-HIIA were determined in two urine portions after 45 and after consecutive 45 min of exposure. Total amounts of excreted 5-HIIA and creatinine in the first urine portion in (I) and (II) were significantly higher in comparison with normal values; they did not depend on the amount of urine voided. The 5-HIIA excretion was significantly higher in smokers after the first 45 min of exposure only. Total amounts of excreted 5-HIIA and creatinine after another 45 min of exposure in (I) and (II) were significantly lower. The high correlation has been found between excretion of 5-HIIA and creatinine, indicating a similar process of excretion of both substances. Hydratation before the thermal stress exerted advantageous effect on the thermoregulation in men. The results of this study have been discussed in conjunction with the data in literature.

[Effect of long-term work in hot microclimate on various physiological parameters in metallurgists]. / Wplyw dlugoletniej pracy w goracym mikroklimacie na niektóre parametry fizjologiczne u hutników.

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.

[New method of determination of carboxyhemoglobin by the conductometric method of extraction of carbon monoxide from the blood]. / Nowa metoda oznaczania zawartosci hemoglobiny tlenkoweglowej z pomiaru tlenku wegla we krwi.

The newly elaborated method consists in the gasometric CO determination in the blood. The extraction of CO from the blood sample (0,1-1,0 ml) is performed by means of a simple device designed by the authors. The extracted CO is determined by gas analyser ANKO-3 or Ultragas 5. The comparison between the new method and iodometric method showed very high correlation (r greater than 0,9). A discussion follows on the advantages of the new method (quick, easy, high-sensitive and precise), its use can be suggested to laboratories which are equipped with a gas analyser ANKO-3 for other purposes. The new method can be used for numerous routine analyses as well as for scientific studies.