Maestros

Pet Ownership, but Not ACE Inhibitor Therapy, Blunts Home Blood Pressure Responses to Mental Stress
Karen Allen, Barbara E. Shykoff, Joseph L. Izzo, Jr
Abstract—In the present study, we evaluated the effect of a nonevaluative social support intervention (pet ownership) on blood pressure response to mental stress before and during ACE inhibitor therapy. Forty-eight hypertensive individualsparticipated in an experiment at home and in the physician’s office. Participants were randomized to an experimental group with assignment of pet 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, and plasma renin activity were recorded at baseline and after each mental stressor (serial subtraction andspeech). Before drug therapy, mean responses to mental stress did not differ significantly between experimental and control 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] mm Hg), or plasma renin activity (9.4 [0.59] versus 9.3 [0.57] ng · mL 1 · h 1). Lisinopril therapy loweredresting blood pressure by 35/20 mm Hg in both groups, but responses to mental stress were significantly lower among pet owners relative to those who only 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 pressure 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 therapy alone lowers resting blood pressure, whereas increased social support through pet ownership lowers blood pressure response to mental stress. (Hypertension. 2001;38:815-820.) Key Words: blood pressure social support stress lifestyle pets

ntihypertensive agents are known to reliably lower resting blood pressure, but most of these drugs havelittle effect on blood pressure responses to physical or mental stressors.1,2 Because individuals who experience pronounced, frequent, or enduring autonomically mediated cardiovascular responses to stress may be at risk for the development of cardiovascular disease,3,4 variables that moderate or mediate reactivity to stress are important to consider. Several laboratory- and community-based studieshave focused on the potential role of social support in buffering reactivity to mental stress5–9 and have found that when social support participants are perceived as supportive and nonevaluative, a beneficial effect is found. Although considerable attention has been devoted to the definition and measurement of social support as it relates to health,10,11 most of this literature assumes that benefitsare provided only by humans. In recent years, however, several studies have documented that pet animals also can have an important supportive role and a positive influence on the health of their owners. Pet ownership is a significant predictor of 1-year survival after myocardial infarction.12,13 Relative to the support of friends and spouses, the presence of a pet elicits significantly lowerblood pressure and heart rate reactivity during mental stress.5 In addition, elderly individ-

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uals with pets are buffered from the impact of stressful life events and make fewer visits to physicians14; among persons with AIDS, pet owners have a lower incidence of depression than do those without pets.15 Finally, service dogs have a positive influence on the well-being, self-esteem, andcommunity integration of persons with disabilities.16 In the present study, we extended previous laboratory stress-reactivity and social support research to include home data in randomly assigned pet owners administered the ACE inhibitor lisinopril. We hypothesized that the acquisition of a pet would reduce heart rate, blood pressure, and renin responses to psychological stress among a group of...