Chronic fatigue syndrome—a system under stress

November 15, 2012

Australian researchers have discovered for the first time that reduced heart rate variability – or changes in heart beat timing – best predicts cognitive disturbances, such as concentration difficulties commonly reported by people with chronic fatigue syndrome (CFS). This adds to the growing body of evidence linking autonomic nervous system imbalance to symptoms of this poorly understood disorder.

The findings are reported in the journal .

is characterised by medically unexplained, disabling fatigue and of at least six months' duration. The disturbance underlying the symptoms in CFS is still poorly understood.

"We have studied autonomic function in CFS for some time and our findings clearly indicate a loss of integrity in stress-responsive neural and physiological systems in CFS. Patients with this condition are hyper-responsive to challenges arising both from within the body and from the environment," says lead researcher, Associate Professor Ute Vollmer-Conna of the University of New South Wales in Sydney, Australia.

"Even when they sleep, their stress-responsive neural systems are on high alert, signalling that it is not safe to relax. I think this condition may be understood by analogy to post-traumatic stress disorder, just that in CFS the original trauma is most likely a physiological, internal one, such as a severe infection."

In a study of 30 patients with CFS and 40 healthy individuals, UNSW researchers recorded the heart beats of participants (via ECG) and analysed cardiac responses to cognitive challenges, and associations with outcomes.

The patients with CFS performed with similar accuracy, but they took significantly longer to complete the tests than people without the condition. They also had greater heart rate reactivity; low and unresponsive ; and prolonged heart rate-recovery after the cognitive challenge.

variability (an index of vagus nerve activity) was identified as the only significant predictor of cognitive outcomes, while current levels of fatigue and other symptoms did not relate to cognitive performance.

"This is the first demonstration of an association between reduced cardiac vagal tone and cognitive impairment in CFS. Our findings confirm previous reports of a significant loss of vagal modulation, which becomes particularly apparent when dealing with challenging tasks. The current results are consistent with the notion that CFS represents a 'system under stress'," Associate Professor Vollmer-Conna says.

The findings could lead to new ways to improve cognitive difficulties in people with CFS, including biofeedback assisted retraining of autonomic functioning, the researchers say.

Explore further: B-lymphocyte depletion using the anti-CD20 antibody rituximab in chronic fatigue syndrome

More information: dx.plos.org/10.1371/journal.pone.0049518

Related Stories

B-lymphocyte depletion using the anti-CD20 antibody rituximab in chronic fatigue syndrome

October 20, 2011
Chronic fatigue syndrome (CFS) may be alleviated by the anti-cancer drug Rituximab, suggesting that the source of the disease could lie in the immune system, according to a new study published Oct. 19 in the online journal ...

Chronic Fatigue Syndrome challenges patients, medical professionals

July 1, 2011
(Medical Xpress) -- We all get a little tuckered out now and then, but when that tired feeling doesn’t go away with what’s considered normal rest and relaxation there are a myriad of medical conditions that can ...

Study to reveal causes of chronic fatigue syndrome

December 22, 2011
Scientists at the University of Liverpool are the first to use a new laboratory technique that could reveal the causes of Chronic Fatigue Syndrome (CFS).

Recommended for you

A large-scale 'germ trap' solution for hospitals

July 26, 2017
When an infectious airborne illness strikes, some hospitals use negative pressure rooms to isolate and treat patients. These rooms use ventilation controls to keep germ-filled air contained rather than letting it circulate ...

Male hepatitis B patients suffer worse liver ailments, regardless of lifestyle

July 25, 2017
Why men with hepatitis B remain more than twice as likely to develop severe liver disease than women remains a mystery, even after a study led by a recent Drexel University graduate took lifestyle choices and environments ...

Mind-body therapies immediately reduce unmanageable pain in hospital patients

July 25, 2017
Mindfulness training and hypnotic suggestion significantly reduced acute pain experienced by hospital patients, according to a new study published in the Journal of General Internal Medicine.

Researchers report new system to study chronic hepatitis B

July 25, 2017
Scientists from Princeton University's Department of Molecular Biology have successfully tested a cell-culture system that will allow researchers to perform laboratory-based studies of long-term hepatitis B virus (HBV) infections. ...

Research examines lung cell turnover as risk factor and target for treatment of influenza pneumonia

July 24, 2017
Influenza is a recurring global health threat that, according to the World Health Organization, is responsible for as many as 500,000 deaths every year, most due to influenza pneumonia, or viral pneumonia. Infection with ...

Scientists propose novel therapy to lessen risk of obesity-linked disease

July 24, 2017
With obesity related illnesses a global pandemic, researchers propose in the Journal of Clinical Investigation using a blood thinner to target molecular drivers of chronic metabolic inflammation in people eating high-fat ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.