In a recent study, researchers find that sympathetic nerve activity in skeletal muscle blood vessels increases during body and mental stress in people with chronic anxiety.
Over time, this response may increase the risk of high blood pressure and heart disease.
sympathetic nerve activity is a function of the nervous system that helps regulate blood pressure.
The researchers from the University of Iowa studied the responses of two groups of people after they experienced body and mental stressors.
One group of people had chronic anxiety. The control group did not have anxiety.
The research team placed the volunteers’ hands in an ice-water bath for two minutes to assess their responses to physiological stress.
After a brief 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 “warning” countdown.
The research team inserted a tiny microelectrode into a nerve near the back of the participants’ knee to measure 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.
They found that the anxiety group had higher levels of norepinephrine, a hormone that sympathetic nerve fibers release in response to stress, before testing began.
Norepinephrine causes the blood vessels to contract, which raises blood pressure.
The researchers also observed increased nerve responses in both groups before and during the ice bath and math activities.
However, the increase was much higher in the anxiety group compared with the control group.
The team also found heart rate increased during the two-minute countdown, another sign that the anticipation of impending stress or discomfort caused physiological changes in the body. And there was no significant difference between the anxiety and control groups.
Their future work will examine whether sympathetic nerve activity related to anxiety, cardiovascular disease risks.
The study is published in the Journal of Neurophysiology.
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News source: American Physiological Society.
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