Autonomic nervous system out of balance in people with hEDS: Study
Cardiovascular reflex tests can be useful for monitoring autonomic dysfunction
Young adults with hypermobile Ehlers-Danlos syndrome (hEDS) exhibit signs of an imbalance in the body’s autonomic nervous system, according to a recent study.
The autonomic nervous system is responsible for regulating involuntary bodily functions such as heart rate, blood pressure, breathing, and digestion. The observed imbalance was linked to symptoms including high heart rate, low blood pressure, and increased breathing rate.
The study, “A Cross-Sectional Study of Cardiovascular Autonomic Reactivity in Ehlers-Danlos Syndrome,” was published in Cureus.
The most common type of Ehlers-Danlos syndrome, hEDS is mainly recognized by its hallmark symptoms of fragile skin, overly mobile joints, and musculoskeletal pain.
Autonomic dysfunction common in hEDS, can affect life quality
However, autonomic dysfunction, or dysautonomia, is also common and can significantly affect life quality. Symptoms of autonomic dysfunction may include heart rate and blood pressure changes, bladder and gastrointestinal issues, or sweating problems.
The autonomic nervous system includes the sympathetic and parasympathetic nervous systems. The sympathetic nervous system mediates what’s commonly known as the body’s “fight or flight” response, where the body is put on high alert and resources are diverted to increase energy expenditure. The parasympathetic nervous system helps restore the body to a resting state, sometimes called “rest and digest.”
The balance between these two essential systems is called autonomic tone. If they’re out of balance, it can lead to problems like elevated heart rate and low blood pressure, which are commonly observed in EDS.
Over time, this imbalance increases the risk of more serious cardiovascular problems, so it is important to understand whether autonomic tone is altered in hEDS and to have a good way of monitoring it, according to the researchers.
As such, they examined autonomic tone in a group of 30 hEDS patients, ages 18-25, at their research center in India. They also examined 30 healthy people in the same age range, who served as a control group.
The patients had a significantly higher resting heart rate, lower blood pressure, and a faster breathing rate than the control group, which the researchers indicated “can be attributed to autonomic dysfunction.”
Noninvasive cardiovascular reflex tests can assess autonomic tone
Autonomic tone was assessed using noninvasive screening measures collectively called cardiovascular reflex tests, which look at heart rate and blood pressure changes in response to activities intended to activate either the parasympathetic or sympathetic system.
Results from the cardiovascular reflex tests overall indicated a reduction in function of the parasympathetic nervous system in the patient group relative to the control group across tests, along with a heightened sympathetic nervous system.
When rising from a sitting to a standing position, hEDS patients experienced a notable reduction in blood pressure along with a rise in heart rate, which the researchers believe can be explained by the body’s exaggerated reaction to changes in blood circulation and changes in the release of certain nerve signaling chemicals.
Altogether, the observed imbalance in the autonomic nervous system “may contribute to the observed clinical features, including tachycardia [fast heart rate] and a drop in [blood pressure],” the researchers wrote.
Beyond demonstrating that autonomic dysfunction is evident in hEDS, the findings also indicate that cardiovascular reflex tests are useful tools for monitoring it. Not only could this series of tests be used to identify the presence and severity of autonomic dysfunction in the clinic, but also “might offer valuable insights into the long-term risk to predict morbidity and mortality of cardiovascular complications in EDS patients,” the team concluded.
Still, given the small size of the study, the researchers recommended larger and longer studies be conducted “to obtain more conclusive results.”
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