Crowding in prison: the relationship between changes in housing mode and blood pressure

The relationship between change in mode of housing and corresponding blood pressure (BP) change was investigated among 568 male prisoners as an analogue to animal studies which have shown that crowding elevates BP. The transfer from single occupancy cells to multiple occupancy dormitories was associated with a statistically significant mean increase in systolic blood pressure (SBP). In contrast, men who remained in single cells had little mean change in SBP over time. Inmates who were retransferred to cells after a short stay in dormitories experienced a mean decline in SBP, which suggests that crowding may be reversible in its early stages. SBP also decreased after continued stay in the dormitories, indicating that adaptation may occur. The implications of these findings for crowding theory and their contribution to an understanding of response to the prison environment are discussed.