At any moment, each of these specialized brain neurons might be receiving multiple messages from multiple sources, but is only selectively responding to certain information about the timing or frequency of the impulses it is receiving. Related Stories.
Methods for measuring sympathetic nervous system activity. Heart rate variability (HRV), the beat-to-beat variation in heart rate, is an indirect method of measuring autonomic nervous system activity, with contributions from both the sympathetic and parasympathetic nervous systems.ine electrodes are used to record 'bursts' of activity from multiple or single afferent and efferent nerve axons in the skin and muscle. The common peroneal nerve is typically chosen for this method (because it is easily accessible) and measures the efferent postganglionic muscle sympathetic nerve activity (MSNA).
In one study we attempted to define the relationship of changes in heart rate, sympathetic activity, and ventricular dimensions in the cardiovascular response to mild exercise (performed on a bicycle ergometer in the supine position).Subjects were a group of patients being reevaluated some months after cardiac surgery.hus the sympathetic nervous system did appear to play a compensatory role in the circulatory adjustment of patients to heart failure. The findings also suggested a need for caution in the clinical use of adrenergic-blocking agents to treat patients with limited cardiac reserve.