Effect of seasonal and intermittent work at high altitude on health status.

Health status of 7 men was examined in order to study the effect of duty work cycle of 3-d stay at the altitude of 2,000 m and one-day holiday at 600 m for a period of 6 months from May to October. Their usual works were desk work and road patrol. Total hemoglobin concentration in blood increased significantly after work at high altitude, which was considered to be a compensatory response to the hypoxic state. Subjective symptoms were obtained by a self-administered questionnaire before (April), during (June and October) and after (November) work at high altitude. Fatigue was observed in three out of the seven subjects in June, which subsequently disappeared in October. Dyspnea was observed also in June in three of the subjects, which disappeared in two, persisted in one, and newly appeared in another subject in November. In contrast, a tendency of favorable effects of the work environment on nausea and lumbago was observed. Blood pressure and pulse rate were measured for 24 h. The mean systolic blood pressure during 24 h decreased in two of five subjects in October and November, and the mean values during the working hours decreased in two in October from 145 to 131 mmHg and from 147 to 129 mmHg, respectively. The blood pressure measured at health examination correlated well with the mean blood pressure during 24 h and working hours. The mean pulse rate during 24 h and working hours increased in one in June, October and November. These results indicate that adaptive responses to low barometric pressure environment developed during a work period of 5 months at high altitude.(ABSTRACT TRUNCATED AT 250 WORDS)