Researchers at the Universitat Autònoma de Barcelona (UAB), Universitat Politècnica de Catalunya BarcelonaTech (UPC), and Vall d'Hebron, have developed a mobile application that could be useful in the assessment of the severity of fatigue in chronic fatigue syndrome, especially in women. The technology uses a chest strap that measures heart rate variability.

The results of the study in which this technology has been tested have been published in the journal Sensors.

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Chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) is a debilitating condition, in which people have great difficulties in carrying out their daily activities. Severe fatigue is the main symptom of CFS/ME, in addition to problems with immediate memory and speed of information processing and concentration, intolerance to physical/mental exercise, pain, and dizziness. Despite its high prevalence, there are still no effective tools for its diagnosis, monitoring, and treatment.

In Catalonia, it is estimated that there are currently between 350,000 and 500,000 people affected by chronic fatigue syndrome/myalgic encephalomyelitis, and 2 out of 3 affected people are women. Worldwide, a prevalence of between 17 and 25 million people with this affectation is estimated.

The technology developed by the UAB and UPC researchers consists of a chest strap with a sensor capable of measuring certain cardiac hemodynamic variables, connected via Bluetooth to a mobile app. The mobile application allows you to record and monitor heart rate variability and share the analyzed results with the medical staff who supervise patients, reports UAB.

Specifically, this study analyzed the relationship between heart rate variability and severity of symptoms among women and men with CFS/ME. This parameter is closely related to heart rate, that is, the number of beats per minute of the heart. However, the time that passes between two consecutive beats is not always exactly the same, but small differences that fall within normality can be detected: this is what is known as heart rate variability (HRV).

In previous studies, HRV had already been related to the assessment of the severity of fatigue in women with CFS/ME. "Specifically, we had observed that this variability was lower in patients with CFS/ME, especially in the most disabling cases", explains Dr. Jesús Castro, coordinator of the laboratory in Chronic Fatigue Syndrome/Myalgic Encephalomyelitis of the Rheumatology group of the Vall d'Hebron Research Institute (VHIR). A priori, it is considered positive to have high variability, as it is an indicator of the proper functioning of the autonomic nervous system. "In this work, we wanted to verify the relationship between HRV and the syndrome in both women and men with CFS/ME compared to healthy controls and its usefulness for monitoring patients", adds Dr. Castro.

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In line with previous studies, it was found that HRV measurement with mobile app technology could predict the severity of disabling fatigue in patients with chronic fatigue syndrome/myalgic encephalomyelitis. This was especially observed in the case of women, but this relationship was not so clear in the case of men. "We demonstrated that the use of the app would be especially useful for the monitoring of women suffering from this syndrome, which clearly have a lower variability of heart rate compared to healthy women", says Dr. Rosa M Escorihuela, from the Department of Psychiatry and Legal Medicine of the UAB. Thus, HRV would be a good predictor marker of the severity of fatigue during the clinical course of the disease.