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Baroreflex buffering in sedentary and endurance exercise-trained healthy men
Demetra D Christou1, Pamela Parker Jones, Douglas R Seals
1Department of Kinesiology and Applied Physiology, University of Colorado at Boulder, UCB 354, Boulder, Colo 80309, USA. christou@colorado.edu
Hypertension (Dallas, Tex. : 1979)
|May 7, 2003
Summary
Endurance exercise training does not alter baroreflex buffering in healthy men. This study found similar blood pressure regulation mechanisms in trained and untrained individuals, suggesting vigorous exercise doesn't change this vital control system.
Area of Science:
- Cardiovascular Physiology
- Exercise Physiology
- Autonomic Nervous System Regulation
Background:
- Baroreflex buffering is crucial for maintaining arterial blood pressure.
- Previous research indicates potential alterations in baroreflex sensitivity with endurance training.
- The in vivo baroreflex buffering in endurance-trained humans remains largely uninvestigated.
Purpose of the Study:
- To investigate whether in vivo baroreflex buffering differs between endurance exercise-trained and untrained healthy men.
- To assess the impact of habitual vigorous endurance exercise on the body's blood pressure control mechanisms.
Main Methods:
- Baroreflex buffering was assessed in 36 healthy men (18 trained, 18 untrained) using phenylephrine bolus and infusion during ganglionic blockade.
- Measurements included systolic blood pressure responses to phenylephrine and heart rate variability.
- Maximal oxygen consumption and resting heart rate were used to confirm training status.
Main Results:
- Endurance-trained men exhibited lower resting heart rate and higher maximal oxygen consumption, confirming their training status.
- No significant differences were observed in mean blood pressure, cardiovagal baroreflex sensitivity, or sympathetic nerve activity between groups.
- Systolic blood pressure responses to phenylephrine and measures of baroreflex buffering were similar in both trained and untrained men.
Conclusions:
- Habitual vigorous endurance exercise does not appear to modulate in vivo baroreflex buffering in healthy humans.
- These findings suggest that the autonomic nervous system's blood pressure regulation via baroreflex buffering is not significantly altered by endurance training.
- The study supports the concept that the baroreflex buffering system remains consistent regardless of endurance exercise status in healthy individuals.