Search

The aim of the study was to determine the degree to which the heart rate during and after work of variable physical and mental load was affected by the mental workload of moderate intensity. The subjects were 150 women aged 17-57. 24-hour recordings of their heart rates during work, leisure and sleep were taken using the Medilog recording-analysing system. Mental workload was determined in two ways: by the AET method, which enabled objective evaluation of the load, and by a method which involved subjective evaluation of work requirements and the ability to cope with them. Using the multiple regression analysis, the degree to which concurrent elements of mental and physical workload an serve as predictors of heart rate during work, leisure and sleep. The results show that physical workload is the more essential factor affecting the reaction of the circulatory system under the circumstances of concurrent mental and physical workload. By extending the measurements to involve off-duty hours, it was possible to determine that the consequences of mental workload manifested also after the work. The prolonged effect of mental workload on the heart rate was evident only when the subjective method of workload estimation was used. This points to the individual character of mental workload. The findings indicate on one hand that the share of mental workload should not be neglected during evaluation of the effects of occupational workload on the physiological reactions and, on the other, that the heart rate measurement is a useful tool for indicating essential elements of workload.

In order to evaluate the effect of particular elements of physical workload on the heart rate in a group of 148 women working at 18 work-posts whose jobs were characterized by different physical workload, 24-hour cardiograms were made using Holter's method and applying the Medilog 3000 (Oxford). It was observed that heart rate heart rate during work was higher in women who performed jobs demanding dynamic physical effort, and lower in those subjects who performed static work. Heart rate during work was positively correlated with the dynamic effort intensity and negatively--with the intensity of light dynamic work and static workload, which means that particular elements of physical workload are of different physiological importance. Therefore, the synthetic indicator of physical workload cannot be treated as a sum of the intensity of particular elements. Consequences of physical workload lasted during daytime. During sleep and leisure hours the effect of physical workload intensity upon the cardiac contraction frequency is not significant.

The deficiency of binocular vision calls for an absolute contraindication to perform a number of occupations. It is not easy to evaluate the binocular vision disturbance, especially in young people. Therefore it was decided to check the binocular vision by six methods and compare the results. Among 199 pupils of the seventh form of primary schools, the following binocular vision disturbances have been found: in 18% of subjects on stereometer, in 15% on a projector with polarizing glasses, in 14% lack of protective reflexes, in 13% on stereoscope, in 11,6% on synoptophore and lack of ambiopia after using the prism in 9% of subjects. All the tests yielded negative findings in 5,5% of subjects. The obtained data suggest that it is not enough to use just one method for a thorough determination of binocular vision.

The examinations have been carried out under model conditions in women aged 33.6 +/- 3.8, in whom refraction defects or other sight organ disorders had been excluded. In order to select factors that would be most sensitive and specific for evaluation of visual fatigue, variations in the following indices of the sight organ occupational condition have been analysed: the near vision point, dispersing lens tolerance, retina sensibility, critical fusion frequency, speed and accuracy of perception, visual simple and choice reaction time. The indices have been analysed under the performance of sigh work and medium-hard physical effort. Variations in the near point and retina irritability have been regarded the most sensitive and specific indices of asthenopia. In addition, intra- and interpersonal variability, as well as seasonal variability of the indices listed have been assessed. Significant seasonal differences have been found between the values measured in the persons prior to work in summer and winter for near vision sense point, dispersing lens tolerance, retina irritability, and critical fusion frequency.

The results of all the efforts made so far towards the reduction of CS2 concentrations at the workplaces of viscose rayon industry indicate that achievement of safe standards is little probable in the nearest future. Likewise, the preventive activities aimed at the reduction of the daily working time from 8 to 6 hours and referring workers to work with no exposure for several months are hardly effective. Basing on the results of clinical and epidemiological studies of the CS2 exposed population and relevant control groups the authors indicate their own solutions of decreasing the health risk. Pursuant to this suggestion the total time of work in exposure should not exceed 15 years and would be interrupted by so called periods of "health regeneration", consisting in the transfer to the production with no CS2 exposure for one year. This rotational system would apply to all those employed for over five years under CS2 concentrations exceeding the hygienic standards.