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Neurovascular responses to mental stress
Jason R Carter1, Nathan T Kupiers, Chester A Ray
1Department of Medicine, Pennsylvania State College of Medicine, 500 University Drive, Hershey, PA 17033-2390, USA.
The Journal of Physiology
|February 12, 2005
Summary
Mental stress impacts arm blood flow but not leg blood flow, with no immediate change in muscle sympathetic nerve activity. However, sympathetic nerve activity significantly increases after stress, potentially affecting cardiovascular health.
Area of Science:
- Cardiovascular Physiology
- Neuroscience
- Human Physiology
Background:
- Previous research studied mental stress (MS) effects on muscle sympathetic nerve activity (MSNA) and limb blood flow independently.
- The collective neural and vascular responses to MS in both the arm and leg remain unexamined.
- Cardiovascular implications of post-MS responses require further investigation.
Purpose of the Study:
- To comprehensively investigate concurrent neural and vascular responses during and after mental stress in both the arm and leg.
- To elucidate the differential control of limb vasculature during and after mental stress.
- To explore the cardiovascular implications of post-mental stress recovery.
Main Methods:
- Study 1: Measured MSNA, blood flow (plethysmography), mean arterial pressure (MAP), and heart rate (HR) in arm and leg during/after 5-min mental arithmetic in 12 healthy subjects.
- Study 2: Measured forearm and calf blood flows using Doppler ultrasound in 10 additional subjects during/after mental stress.
- Calculated forearm vascular resistance (FVR) and calf vascular resistance (CVR).
Main Results:
- Mental stress significantly increased MAP and HR but did not alter MSNA in either limb during the stress period.
- MS decreased FVR but did not change CVR, indicating differential vascular control between the arm and leg.
- During recovery, FVR returned to baseline, while MSNA significantly increased in both the arm and leg.
Conclusions:
- Differential vascular control of the arm and leg occurs during mental stress, independent of concurrent muscle sympathetic outflow.
- A notable increase in muscle sympathetic nerve activity during the recovery phase following mental stress was observed.
- The heightened MSNA during recovery may have significant acute and chronic cardiovascular implications.