New Study Reveals Link between Sympathetic Nerve Activity and Chronic Anxiety


Researchers from the University of Iowa reported increase in Sympathetic nerve activity to skeletal muscle blood vessels during physiological and mental stress in people suffering from chronic anxiety

The study was published in the Journal of Neurophysiology on May 2, 2018. Study reported that increasing chronic anxiety may also increase the risk of high blood pressure and heart disease. However this was not proved experimentally with certain tests. As a part of the study, the team studied responses of two groups of volunteers after they experienced physiological and mental stress.

Participants were divided into two groups, one group had people suffering from had chronic anxiety, which was determined by standardized scales to measure anxiety and depression. Other was control group lacking anxiety. Volunteers’ hands were inserted in an ice-water bath for two minutes to assess their responses to physiological stress. After recovery period, the participants verbally solved simple math problems as fast as they could for four minutes to induce mental stress. Before the start of each test, the researchers gave the participants a two-minute countdown.

Furthermore, tiny microelectrode were inserted into a nerve near the back of the participants’ knee, which measured sympathetic nerve activity throughout testing. They monitored the volunteers’ rate of blood flow and blood pressure in the upper arm and heart rate via a finger cuff during both activities. Results of the blood samples showed that anxiety group had higher levels of norepinephrine, a hormone that sympathetic nerve fibers release in response to stress, before testing began. Increased nerve responses were observed in both groups before and during the ice bath and math activities. It was found that increase was higher among anxiety group as compared to the control group. Furthermore, researchers are working on examining effect of anxiety on risk factors for developing cardiovascular disease.


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