Pet ownership, but not ACE inhibitor therapy, blunts home blood pressure responses to mental stress

In the present study, we evaluated the effect of a nonevaluative social sup port intervention (pet ownership) on blood pressure response to mental stre ss before and during ACE inhibitor therapy. Forty-eight hypertensive indivi duals participated in an experiment at home and in the physician's office. Participants were randomized to an experimental group with assignment of pe t ownership in addition to lisinopril (20 mg/d) or to a control group with only lisinopril (20 mg/d). On each study day, blood pressure, heart rate, a nd plasma renin activity were recorded at baseline and after each mental st ressor (serial subtraction and speech). Before drug therapy, mean responses to mental stress did not differ significantly between experimental and con trol groups in heart rate (94 [SD 6.8] versus 93 [6.8] bpm), systolic blood pressure (182 [8.0] versus 181 [8.3] mm Hg), diastolic blood pressure (120 [6.6] versus 119 [7.9] min Hg), or plasma renin activity (9.4 [0.59] versu s 9.3 [0.57] ng.mL(-1).h(-1)). Lisinopril therapy lowered resting blood pre ssure by approximate to 35/20 min Hg in both groups, but responses to menta l stress were significantly lower among pet owners relative to those who on ly received lisinopril (P<0.0001; heart rate 81 [6.3] versus 91 [6.5] bpm, systolic blood pressure 131 [6.8] versus 141 [7.8] mm Hg, diastolic blood p ressure 92 [6.3] versus 100 [6.8] mm Hg, and plasma renin activity 13.9 [0. 92] versus 16.1 [0.58] ng.mL(-1).h(-1)). We conclude that ACE inhibitor the rapy alone lowers resting blood pressure, whereas increased social support through pet ownership lowers blood pressure response to mental stress.