[Effect of night-shift work on selected physiological indicators in power plant workers]

Ninety-two workers of Thermal-electric Power Station have been examined. The subjects have been classified into three age-dependent groups: 21-30, 31-40 and over 40 years. Each of the subjects has undergone tests of selected physiological indices before and after the night shift. The examinations included: body temperature measurement, pulse rate, respiration rate, arterial blood pressure. The measurements promoted calculation of: Kerdö's index pulse respiration rate, mean arterial pressure, stroke and minute volumes. Changes in physiological indices due to night work have been compared in particular age groups by the "t" Student test for two mean values of small samples. The night work results in hypertonia of the vegetative parasympathetic system which is consistent with the circadiem rhythmicity of human physiological functions. The 21-30 years age group exhibits strong excitation of the vegetative sympathetic system due to great nervous and emotional tension accompanying operators' work.