Attenuated blood pressure responsiveness during post-exercise hypotension

ORCID

J. Mark Van Ness: https://orcid.org/0000-0001-5902-8735

Document Type

Article

Publication Title

Clinical and Experimental Hypertension

Department

Health, Exercise, and Sport Sciences Department

ISSN

1064-1963

Volume

18

Issue

7

DOI

10.3109/10641969609097906

First Page

891

Last Page

900

Publication Date

1-1-1996

Abstract

Objective: To test the hypotheses that acute treadmill exercise would produce post-exercise hypotension (PEH) and that PEH would be associated with reduced mean arterial pressure (MAP) responsiveness to the α1-adrenergic agonist phenylephrine.Methods: Arterial and venous catheters were implanted into exercise-trained female Dahl-salt sensitive rats (n=9) for measurement of pulsatile blood pressure (BP) and heart rate (HR). The changes in BP following ganglionic blockade (hexamethonium/atropine) and the MAP responses to phenylephrine (PE) injections after ganglionic blockade (GB) were examined on separate days in testing cages (control) and following 40 min of treadmill exercise (post-ex). Results: Thirty minutes following graded treadmill exercise (20-40 m/min, 0% grade, 40 min duration) blood pressure was significantly reduced (-9 ± 1) mmHg compared to control. After exercise, GB produced a 43 ± 3 mmHg decrease in BP which tended (p=0.08) to be less than the reduction observed during control studies (51 ± 2 mmHg). PE-induced increases in BP were significantly lower post-ex than control for each of the dosages tested (0.5, 1.0 and 2.0 ug/kg). Conclusions: These results demonstrate that there is sustained reduction in PE-induced MAP responsiveness which accompanies exercise-induced decreases in blood pressure in the Dahl salt-sensitive rat. Thus, decreased alpha-adrenoceptor responsiveness may contribute to the production of PEH.

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