Cardiovascular responsiveness to sympathoexcitatory stress in subjects with and without mild hypertension

Carthy, Elliott R., White, Leigh, Russell, Fraser D., Holmes, Mark, Leicht, Anthony S., Brooks, Peter R., Hitchen-Holmes, Deborah, and Askew, Christopher D. (2015) Cardiovascular responsiveness to sympathoexcitatory stress in subjects with and without mild hypertension. Clinical Physiology and Functional Imaging, 35. pp. 150-158.

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Abstract

Purpose: This study compared blood pressure, heart rate variability (HRV) and forearm blood flow, at rest and in response to sympathoexcitatory stressors between normotensive and mildly hypertensive participants. Methods: Participants aged 30–79 years with normal blood pressure (n = 49) or mild hypertension (n = 17), with no history of taking antihypertensive medication, were recruited. Participants completed a cold pressor test (CPT) followed by an ischaemic handgrip test (IHGT). Blood pressure, HRV, forearm blood flow and vascular resistance were measured at rest and in response to each test. Results: The CPT and IHGT evoked greater increases in mean arterial blood pressure in hypertensive participants (CPT: 10 ± 2 mmHg, IHGT: 9 ± 1 mmHg) compared with normotensive participants (CPT: 5 ± 1 mmHg, IHGT: 3 ± 1 mmHg; P<0.05). Resting high frequency power, which is a parameter of HRV associated with parasympathetic cardiac modulation, was lower in hypertensive participants (hypertensive: 31.73 ± 4.07 nu; normotensive: 42.08 ± 2.22 nu; P = 0.026) and was negatively correlated with systolic blood pressure (r = -0.272, P = 0.03) and mean arterial pressure across all participants (r = -0.258, P<0.05). There were no differences in HRV or forearm blood flow responses to the CPT or IHGT between groups. Conclusion: This study demonstrated that sympathoexcitatory stress evoked by the CPT and IHGT induces an augmented blood pressure response in individuals with mild hypertension, which supports the notion that autonomic dysfunction is likely to contribute to the pathogenesis of hypertension. It remains to be determined whether the hypertensive response is mediated through alterations in cardiac activity, peripheral vascular resistance or both.

Item ID: 35198
Item Type: Article (Research - C1)
ISSN: 1475-097X
Keywords: blood pressure; cardiac autonomic modulation; cold pressor test; ischaemic handgrip test; vascular resistance
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Funders: University of the Sunshine Coast
Date Deposited: 03 Sep 2014 23:48
FoR Codes: 11 MEDICAL AND HEALTH SCIENCES > 1102 Cardiovascular Medicine and Haematology > 110201 Cardiology (incl Cardiovascular Diseases) @ 30%
11 MEDICAL AND HEALTH SCIENCES > 1106 Human Movement and Sports Science > 110602 Exercise Physiology @ 70%
SEO Codes: 92 HEALTH > 9201 Clinical Health (Organs, Diseases and Abnormal Conditions) > 920103 Cardiovascular System and Diseases @ 70%
92 HEALTH > 9299 Other Health > 929999 Health not elsewhere classified @ 30%
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