Cardiovascular reactivity to behavioral stress in young males with and without marginally elevated casual systolic pressures. Comparison of clinic, home, and laboratory measures.

Heart rate (HR), systolic (SBP), and diastolic (DBP) blood pressure levels were compared in 60 young males during various resting and stressful conditions. Subjects included 29 who had and 31 who had not shown occasional casual SBP readings greater than or equal to 135 mm Hg under low stress conditions. These groups were further divided into those who showed above-average and below-average HR increases at onset of a stressful shock-avoidance task (high vs low HR reactors). High HR reactors, who were equally distributed in both casual SBP groups, also showed higher SBP than low reactors during avoidance, and higher HR and SBP during a pre-stress rest period and two other stresses, the cold pressor test and viewing an erotic film (p's less than 0.01). During less stressful conditions (relaxation in the laboratory, family doctor readings, and self-determinations at home), no HR, SBP, or DBP differences were seen between high and low HR reactors. Subjects with casual SBPs greater than or equal to 135 showed higher mean SBP than those with casual SBPs less than 135 under all resting and stressful conditions (p's less than 0.05) and generally higher DBP as well. Highest mean SBP levels during prestress rest and later stresses were shown by subjects with both casual SBPs greater than or equal to 135 and high HR reactivity to the avoidance task, and lowest by subjects with neither trait. Incidence of parental hypertension was greater among high than low HR reactors, and greatest among high reactors with casual SBPs greater than or equal to 135, suggesting that HR reactivity to stress may help predict future hypertension.