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Attenuated blood pressure responsiveness during post-exercise hypotension
J M VanNess1, H J Takata, J M Overton
1Department of Nutrition, Food, and Movement Sciences, Florida State University, Tallahassee 32306-4079, USA.
Clinical and Experimental Hypertension (New York, N.Y. : 1993)
|October 1, 1996
Summary
Acute treadmill exercise caused sustained hypotension in rats. This post-exercise hypotension was linked to reduced blood pressure responses to phenylephrine, suggesting decreased alpha-adrenoceptor responsiveness contributes to this effect.
Area of Science:
- Physiology
- Cardiovascular Science
- Exercise Physiology
Background:
- Post-exercise hypotension (PEH) is a phenomenon where blood pressure remains lower after exercise.
- The underlying mechanisms of PEH, particularly the role of autonomic nervous system responsiveness, require further elucidation.
Purpose of the Study:
- To investigate if acute treadmill exercise induces PEH in Dahl salt-sensitive rats.
- To determine if PEH is associated with altered mean arterial pressure (MAP) responsiveness to alpha 1-adrenergic stimulation.
Main Methods:
- Exercise-trained female Dahl salt-sensitive rats underwent arterial and venous catheterization for blood pressure and heart rate monitoring.
- Mean arterial pressure (MAP) responses to phenylephrine (PE) injections were assessed after ganglionic blockade (GB) following both control conditions and acute treadmill exercise.
Main Results:
- Treadmill exercise resulted in a significant reduction in blood pressure 30 minutes post-exercise compared to control.
- Ganglionic blockade caused a smaller decrease in blood pressure after exercise compared to control.
- Phenylephrine-induced increases in MAP were significantly attenuated post-exercise across all tested dosages.
Conclusions:
- Acute exercise in Dahl salt-sensitive rats leads to sustained hypotension.
- Reduced responsiveness to alpha 1-adrenergic stimulation (phenylephrine) accompanies exercise-induced hypotension.
- Decreased alpha-adrenoceptor responsiveness may be a contributing factor to the development of post-exercise hypotension.