[The effect of fixed night work on blood pressure of male bakery workers in a processing plant]

The effect of fixed night work on blood pressure was investigated for the 13 male bakery workers. All were on the fixed night duty for the first 5 years. The mean BP values of the subjects began to rise significantly from the 4th year. At the 6th year, half of the subjects switched to working in shifts. After that, no increase in the mean BP values was seen in this group. Further increase in the values was observed in the other group on the night duty. However, a two-hour nap late at night prevented the rise of the mean BP values.