Sympathoadrenergic mechanisms in reduced hemodynamic stress responses after exercise.
OBJECTIVE
This study examines the acute effects of moderate aerobic exercise on 1) hemodynamic and sympathetic activity during behavioral stress and 2) beta-adrenergic receptor responsivity in a biracial sample of 24 sedentary adults.


METHODS
Before and after exercise, blood pressure (BP), impedance-derived cardiovascular measures, and plasma norepinephrine (NE) and epinephrine (EPI) were assessed during mental arithmetic and active speech tasks, and beta-adrenergic receptor responsivity was assessed using a standard isoproterenol challenge procedure.


RESULTS
After exercise, BP, NE, and EPI responses to stress were reduced (0.0001 < P < 0.08), preejection period (PEP) was elongated (P < 0.0001), and beta(1)- and beta(2)-receptor responsivity (P < 0.02) was enhanced. Approximately 65% of the prepost exercise mean arterial pressure response difference could be accounted for by changes in sympathetic factors, with change in NE and PEP being the single best predictors.


CONCLUSIONS
Reduced BP responses to stress after acute exercise are strongly linked to a decrease in sympathetic drive, as evidenced by reduced NE responses and elongation of the PEP. Coincident with this overall dampening of the hemodynamic response to stress, increases in cardiac and vascular beta-adrenergic receptor responsivity occur. These findings may have important implications for future translational studies that seek to articulate the mechanisms through which regular aerobic exercise reduces the risks of hypertensive and coronary heart disease.
Brownley
Kimberly A
KA
Department of Psychiatry, University of North Carolina, Chapel Hill 27599, USA. Kim_Brownley@med.unc.edu
Hinderliter
Alan L
AL
West
Sheila G
SG
Girdler
Susan S
SS
Sherwood
Andrew
A
Light
Kathleen C
KC
D000328:Adult; D001794:Blood Pressure / Q000502:physiology*; D003327:Coronary Disease / Q000209:etiology / Q000517:prevention & control; D004837:Epinephrine / Q000097:blood; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000209:etiology / Q000517:prevention & control; D008297:Male; D009638:Norepinephrine / Q000097:blood; D011943:Receptors, Adrenergic, beta / Q000502:physiology*; D013315:Stress, Psychological; D013564:Sympathetic Nervous System / Q000502:physiology*
D011943:Receptors, Adrenergic, beta; D009638:Norepinephrine; D004837:Epinephrine