Blood pressure response to cold pressor test in siblings of hypertensives.

One hundred and five female and thirty-four male student volunteers were divided into three groups. Each group was again divided into siblings of hypertensives (SH) and siblings of normotensives (C). SH group had higher basal seated and supine Systolic and Diastolic Blood Pressures (SBPs and DBPs, respectively). During cold pressor test (CPT), the SH group showed higher rise of SBPs and DBPs. All the volunteers were again regrouped as hyperreactors (HR) (the criteria of a rise of more than 22 mmHg systolic and 18 mmHg diastolic blood pressure during (CPT) and normoreactors (NR). HR showed higher resting seated SBPs and DBPs, and higher rise of SBPs & DBPs during CPT as compared to control groups. The rise in SBPs and DBPs in hyperreactors was significantly higher than SH groups only in 16-19 years female group. The rise of SBPs and DBPs during CPT were also higher in HR as compared to NR of all age groups. The rise of SBPs and DBPs during CPT was significantly higher in controls than in NR in the two female groups. The study suggests that identification of hyperreactors in population gives a better indication of potential hypertensives of future than the children of hypertensives.