RESUMEN
The purpose of this study was to determine the effect of job strain intensity on blood pressure [BP] during nurses' work shifts in the hospitals of Mashad University of Medical Sciences. For this descriptive cross-sectional study, 150 nurses who met the inclusion criteria were chosen by cluster sampling. A questionnaire was used to gather the data including personal characteristics, height, weight and intensity of job strain. Blood pressure was measured three times: in the beginning, middle and the end of the work shift. Women constituted 79% of the participants, and 80% were married. Eighty-nine percent of nurses had a Bachelor's Degree, and 31% had BMI>25. There was a significant relationship between job strain and age, marital status and the hospital unit where they worked. The results imply the significant effect of job strain on the difference in first-second, and second-third systolic BP, but not on differences between diastolic BPs. General linear models indicate a significant relationship between working in emergency unit and first-second systolic BP variations. Marriage and divorce have significant relationship with the first-third systolic BP variations. In this study job strain had a significant effect on nurses' systolic BP at shift work