May 1, 1988Journal of Applied Physiology
Autonomic mediation of the pressor responses to isometric exercise in humans
Why the study?
Does isometric handgrip exercise alter arterial pressure, heart rate, and muscle sympathetic nerve activity in healthy subjects?
Population
8 healthy subjects
Comparison
2.5 min of isometric handgrip exercise at 15… vs Resting state before exercise (control)
Design
Other
Follow-up
2.5 minutes
Authors
Discussion
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Implication
Supports sympathetic mediation of pressor responses during isometric exercise in health; hypothesis-generating and should not change clinical practice.
Key Points
- This study aims to identify the roles of tachycardia and sympathetic nerve activity in blood pressure responses during different intensities of isometric exercise.
- Microneurographic measurements of muscle sympathetic nerve activity were conducted on eight healthy subjects.
- Arterial pressure and heart rate were recorded during 2.5 minutes of isometric handgrip exercise at 15%, 25%, and 35% of maximal voluntary contraction.
- Comparative analysis of arterial pressure and sympathetic nerve activity before, during, and after exercise sessions.
- At 15% MVC, arterial pressure increased by 7 mmHg (P<0.05) during the initial 1.5 minutes of exercise.
- At higher intensities (25% and 35% MVC), arterial pressure increased by 22 mmHg and 34 mmHg, respectively (P<0.05).
- Muscle sympathetic nerve activity increased progressively at 25% and 35% MVC, peaking at 109% and 205% compared to control (P<0.05).
Structured PICO
Does isometric handgrip exercise alter arterial pressure, heart rate, and muscle sympathetic nerve activity in healthy subjects?
P
Population
8 healthy subjects
I
Intervention
2.5 min of isometric handgrip exercise (IHE) at 15, 25, or 35% of maximal voluntary contraction (MVC)
C
Comparator
Resting state before exercise (control)
O
Outcome
Arterial pressure (AP), heart rate (HR), and muscle sympathetic nerve activity (SNA)surrogate
Increases in arterial pressure during fatiguing isometric exercise are directly related to progressive increases in muscle sympathetic nerve activity.
Cite This Study
Seals et al. (1988) studied this question.