Sex differences in post-exercise fatigue and function in myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

To assess biobehavioral sex differences in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) utilizing a low burden exercise protocol, 22 females and 15 males with ME/CFS and 14 healthy controls underwent two six-min walk tests.

Fifteen daily assessments were scheduled for fatigue and function ratings and heart monitoring. Six-min walk tests were conducted on days 8 and 9. The ME/CFS group showed high self-report fatigue and impaired physical function, whereas healthy controls did not show fatigue or function abnormalities.

In patients, no significant post-exercise changes were found for heart rate variability (HRV); however, heart rate decreased in ME/CFS males from Day 14 to Day 15 (p = 0.046). Female patients showed increased fatigue (p = 0.006) after the initial walk test, but a downward slope (p = 0.008) in fatigue following the second walk test. Male patients showed a decrease in self-report work limitation in the days after exercise (p = 0.046). The healthy control group evidenced a decrease in HRV after the walk tests from Day 9-14 (p = 0.038).

This pilot study did not confirm hypotheses that females as compared to males would show slower exercise recovery on autonomic or self-report (e.g. fatigue) measures. A more exertion-sensitive test may be required to document prolonged post-exertional abnormalities in ME/CFS.

Trial registration: NCT NCT03331419.

Source: Friedberg F, Adamowicz JL, Bruckenthal P, Milazzo M, Ramjan S, Zhang X, Yang J. Sex differences in post-exercise fatigue and function in myalgic encephalomyelitis/chronic fatigue syndrome. Sci Rep. 2023 Apr 3;13(1):5442. doi: 10.1038/s41598-023-32581-w. PMID: 37012343. https://www.nature.com/articles/s41598-023-32581-w (Full text)

An international survey of experiences and attitudes towards pacing using a heart rate monitor for people with myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

Background: Myalgic encephalomyelitis (ME) is a complex, multi-system neurological condition. The defining feature of ME is post-exertional malaise (PEM) with over 30 symptoms triggered by physical, cognitive, emotional and social activity.

The cause of PEM is unclear but one area of research using cardio-pulmonary exercise tests show a reduced ventilatory anaerobic threshold (VAT) with repeated tests leading to PEM.

Pacing with heart rate monitoring (HRM) provides feedback to maintain activity intensity below the VAT. There is only one piece of research investigating the use of HRM although a number of guidelines recommend it.

Objective: To identify the experiences and attitudes of people with ME towards HRM.

Methods: A 40 question online survey was devised and released on ME websites, Twitter and Facebook pages. People with ME read the information sheet and followed an online link to the survey. The survey was open for three weeks and all answers were anonymous.

Results: 488 people with ME completed the survey. Most participants were female, 35-50 years and with a reported illness of greater than 5 years. Over 100 types of HR monitor used. Over 30 benefits and over 30 negatives identified. HRM reduced severity of ME and severity and duration of PEM.

Conclusion: Although there are limitations, HRM has many benefits including helping PwME to understand and manage their PEM and support them to increase their activities, including work. There is a need for more research and education of healthcare professionals in the safe use of HRM.

Source: Clague-Baker N, Davenport TE, Madi M, Dickinson K, Leslie K, Bull M, Hilliard N. An international survey of experiences and attitudes towards pacing using a heart rate monitor for people with myalgic encephalomyelitis/chronic fatigue syndrome. Work. 2023 Mar 13. doi: 10.3233/WOR-220512. Epub ahead of print. PMID: 36938766. https://content.iospress.com/articles/work/wor220512 (Full text)

Orthostatic Intolerance and Chronotropic Incompetence in Patients With Myalgic Encephalomyelitis or Chronic Fatigue Syndrome

Abstract:

Background: Orthostatic intolerance markedly affects the day-to-day activities of patients with myalgic encephalomyelitis (ME) or chronic fatigue syndrome. Chronotropic incompetence (CI), defined as an impaired chronotropic response or reduced increases in heart rate during exercise and resulting in lower exercise capacity, may also be observed during orthostasis in patients with ME.

Methods and Results: In this study, the recordings of 101 adult patients with ME (36 men, 65 women; mean [±SD] age 37±12 years) who underwent conventional active 10-min standing tests at least 3 times to determine the presence of CI were analyzed. Recordings were selected for 13 patients who experienced tests both with and without exhibiting postural orthostatic tachycardia syndrome (POTS; an increase in heart rate of ≥30 beats/min or an actual heart rate of ≥120 beats/min) while also both successfully completing and failing to complete 10-min standing on different occasions. Subjects in whom failure without POTS was observed in any test(s) while success was associated with POTS on other occasions were considered positive for CI during orthostasis. Of the 13 patients, 12 (92%) were CI positive, 5 (38%) of whom exclusively failed the tests without experiencing POTS.

Conclusions: Some patients with ME were CI positive during standing tests, suggesting impaired sympathetic activation. The presence of POTS appears to be essential for maintaining orthostasis in these patients.

Source: Kunihisa Miwa. Orthostatic Intolerance and Chronotropic Incompetence in Patients With Myalgic Encephalomyelitis or Chronic Fatigue Syndrome. Circulation Reports, Article ID CR-22-0114. https://www.jstage.jst.go.jp/article/circrep/advpub/0/advpub_CR-22-0114/_html/-char/en (Full text)

Autonomic Nervous System Regulation Effects of Epipharyngeal Abrasive Therapy for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Associated With Chronic Epipharyngitis

Abstract:

Objective: To evaluate the autonomic nerve stimulation effect of epipharyngeal abrasive therapy (EAT) on myalgic encephalomyelitis/chronic fatigue syndrome (CFS) associated with chronic epipharyngitis. Heart rate variability analysis was performed. The study was conducted by analyzing heart rate variability.

Subjects and methods: A total of 29 patients with chronic epipharyngitis who underwent EAT from July 2017 to April 2018 were classified into two groups: 11 patients in the CFS group and 18 patients in the control group without CFS. The patients were classified as phase 1 during bed rest, phase 2 during nasal endoscopy, phase 3 during nasal abrasion, and phase 4 during oral abrasion. Electrocardiographic recordings were made, and autonomic function was compared and evaluated by measuring heart rate, coefficient of variation on R-R interval (CVRR), coefficient of component variance high frequency (ccvHF), and low frequency/ccvHF ratio (L/H) for each of the four phases. The Shapiro-Wilk test was performed to confirm the normality of the two groups, and the parametric test was selected. A repeated measures analysis of variance was performed to assess changes over time between the four events in the two groups. Multiple comparisons were corrected by the Bonferroni method. Comparisons between resting data and three events within each group were performed by paired t-test.

Results: The CFS group had an increased baseline heart rate compared to the control group, and the CFS group had a greater increase in parasympathetic activity and a decrease in heart rate with nasal abrasion. Oral abrasion elicited a pharyngeal reflex and increased heart rate and both sympathetic and parasympathetic activity.

Conclusion: The CFS group was in a state of dysautonomia due to autonomic overstimulation, with an elevated baseline heart rate. The CFS group was considered to be in a state of impaired autonomic homeostasis, with an increased likelihood that overstimulation would induce a pathological vagal reflex and the Reilly phenomenon would develop. The direct effects of EAT on the autonomic nervous system were considered to be vagus nerve stimulation and the regulation of autonomic function by opposing stimulation input to sympathetic and parasympathetic nerves. As an indirect effect, bleeding from the epipharyngeal mucosa due to abrasion was thought to restore the function of the cerebral venous and lymphatic excretory systems and the autonomic nerve center.

Source: Hirobumi I. Autonomic Nervous System Regulation Effects of Epipharyngeal Abrasive Therapy for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Associated With Chronic Epipharyngitis. Cureus. 2023 Jan 14;15(1):e33777. doi: 10.7759/cureus.33777. PMID: 36655156; PMCID: PMC9840732. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9840732/ (Full text)

Dysautonomia in Children with Post-Acute Sequelae of Coronavirus 2019 Disease and/or Vaccination

Abstract:

Long-term health problems such as fatigue, palpitations, syncope, and dizziness are well-known in patients after COVID-19 (post-acute sequelae of coronavirus (PASC)). More recently, comparable problems have been noticed after the SARS-CoV-2 vaccination (post-VAC). The pathophysiology of these problems is not well-understood.

Methods: In 38 children and young adults, we tested if these health problems were related to dysautonomia in an active standing test (Group 1: 19 patients after COVID-19; Group 2: 12 patients with a breakthrough infection despite a vaccination; and Group 3: 7 patients after a vaccination without COVID-19). The data were compared with a control group of 47 healthy age-matched patients, as recently published.

Results: All patients had a normal left ventricular function as measured by echocardiography. Significantly elevated diastolic blood pressure in all patient groups indicated a regulatory cardiovascular problem. Compared with the healthy control group, the patient groups showed significantly elevated heart rates whilst lying and standing, with significantly higher heart rate increases. The stress index was significantly enhanced in all patient groups whilst lying and standing. Significantly decreased pNN20 values, mostly whilst standing, indicated a lower vagus activity in all patient groups. The respiratory rates were significantly elevated in Groups 1 and 2.

Conclusion: The uniform increase in the heart rates and stress indices, together with low pNN20 values, indicated dysautonomia in children with health problems after COVID-19 disease and/or vaccination. A total of 8 patients fulfilled the criteria of postural orthostatic tachycardia syndrome and 9 patients of an inappropriate sinus tachycardia, who were successfully treated with omega-3 fatty acid supplementation and pharmacotherapy.

Source: Buchhorn R. Dysautonomia in Children with Post-Acute Sequelae of Coronavirus 2019 Disease and/or Vaccination. Vaccines (Basel). 2022 Oct 9;10(10):1686. doi: 10.3390/vaccines10101686. PMID: 36298551; PMCID: PMC9607162. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9607162/ (Full text)

Orthostatic Intolerance in Long-Haul COVID after SARS-CoV-2: A Case-Control Comparison with Post-EBV and Insidious-Onset Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Patients

Background: As complaints of long-haul COVID patients are similar to those of ME/CFS patients and as orthostatic intolerance (OI) plays an important role in the COVID infection symptomatology, we compared 14 long-haul COVID patients with 14 ME/CFS patients with a post-viral Ebstein-Barr (EBV) onset and 14 ME/CFS patients with an insidious onset of the disease.
Methods: In all patients, OI analysis by history taking and OI assessed during a tilt test, as well as cerebral blood flow measurements by extracranial Doppler, and cardiac index measurements by suprasternal Doppler during the tilt test were obtained in all patients.
Results: Except for disease duration no differences were found in clinical characteristics. The prevalence of POTS was higher in the long-haul patients (100%) than in post-EBV (43%) and in insidious-onset (50%) patients (p = 0.0002). No differences between the three groups were present in the prevalence of OI, heart rate and blood pressure changes, changes in cerebral blood flow or in cardiac index during the tilt test.
Conclusion: OI symptomatology and objective abnormalities of OI (abnormal cerebral blood flow and cardiac index reduction during tilt testing) are comparable to those in ME/CFS patients. It indicates that long-haul COVID is essentially the same disease as ME/CFS.
Source: van Campen CMC, Visser FC. Orthostatic Intolerance in Long-Haul COVID after SARS-CoV-2: A Case-Control Comparison with Post-EBV and Insidious-Onset Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Patients. Healthcare. 2022; 10(10):2058. https://doi.org/10.3390/healthcare10102058 (Full text)

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Post-COVID Syndrome: A Common Neuroimmune Ground?

Abstract:

A Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating chronic disease of unknown aetiology under growing interest now in view of the increasingly recognized post-COVID syndrome as a new entity with similar clinical presentation.

We performed the first cross-sectional study of ME/CFS in community population in Russia and then described and compared some clinical and pathophysiological characteristics of ME/CFS and post-COVID syndrome as neuroimmune disorders.

Of the cohort of 76 individuals who suggested themselves suffering from ME/CFS 56 subsequently were confirmed as having CFS/ME according to ≥1 of the 4 most commonly used case definition.

Of the cohort of 14 individuals with post-COVID-19 syndrome 14 met diagnostic criteria for ME/CFS. The prevalence of clinically expressed and subclinical anxiety and depression in ME / CFS and post-COVID ME/CFS did not differ significantly from that in healthy individuals.

Severity of anxiety / depressive symptoms did not correlate with the severity of fatigue neigther in ME / CFS nor in post-COVID ME/CFS, but the positive correlation was found between the severity of fatigue and 20 other symptoms of ME / CFS related to the domains of “post-exertional exhaustion”, “immune dysfunction”, “sleep disturbances”, “dysfunction of the autonomic nervous system”, “neurological sensory / motor disorders” and “pain syndromes”.

Immunological abnormalities were identified in 12/12 patients with ME / CFS according to the results of laboratory testing.

The prevalence of postural orthostatic tachycardia assessed by the active standing test was 37.5% in ME / CFS and 75.0% in post-COVID ME/CFS (the latter was higher than in healthy controls, p = 0.02).  There was a more pronounced increase in heart rate starting from the 6th minute of the test in post-COVID ME/CFS compared with the control group.

Assessment of the functional characteristics of microcirculation by laser doppler flowmetry revealed obvious and very similar changes in ME/CFS and post-COVID ME/CFS compared to the healthy controls.  The identified pattern corresponded to the hyperemic form of microcirculation disorders, usually observed in acute inflammatory processes or in deficiency of systemic vasoconstriction influences.

Source: Ryabkova, V.A.; Gavrilova, N.Y.; Fedotkina, T.V.; Churilov, L.P.; Shoenfeld, Y. Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Post-COVID Syndrome: A Common Neuroimmune Ground?. Preprints 2022, 2022090289 (doi: 10.20944/preprints202209.0289.v1) https://www.preprints.org/manuscript/202209.0289/v1 (Full study available as PDF file)

Circadian skin temperature rhythm and dysautonomia in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: the role of endothelin-1 in the vascular dysregulation

Abstract:

Purpose: There is accumulating evidence of autonomic dysfunction in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS); however, little is known about its association with circadian rhythms and endothelial dysfunction. This study aimed to explore the relationship between autonomic responses using an orthostatic test, skin temperature circadian variations, and circulating endothelial biomarkers in ME/CFS.

Methods: Sixty-seven adult female ME/CFS patients and 48 matched healthy controls were enrolled. Demographic and clinical characteristics suggestive of autonomic disturbances were assessed using validated self-reported outcome measures. Postural changes in blood pressure [BP], heart rate [HR], and wrist temperature (WT) were recorded during the orthostatic test. Actigraphy during one week was used to determine the 24-hour profile of peripheral temperature and motor activity. Circulating endothelial biomarkers were also measured as indicators of endothelial functioning.

Results: ME/CFS patients showed higher BP and HR values than healthy controls at rest (p < 0.05 for both), and also higher amplitude of the circadian activity rhythm (p < 0.01). Circulating levels of endothelin-1 (ET-1) and vascular cell adhesion molecule-1 (VCAM-1) were significantly higher in ME/CFS (p < 0.05). In ME/CFS, ET-1 levels were associated with the stability and amplitude of the temperature rhythm, (p < 0.01), and also with the self-reported questionnaires (p < 0.001).

Conclusions: ME/CFS patients exhibited alterations in circadian rhythms and hemodynamic measures that are associated with endothelial dysfunction, supporting previous evidence of dysautonomia in ME/CFS. Future investigation in this area is needed to assess vascular tone abnormalities and dysautonomia which may provide therapeutic targets for ME/CFS.

Source: Trinitat Cambras, Maria Fernanda Zerón-Rugerio, Antoni Díez-Noguera et al. Circadian skin temperature rhythm and dysautonomia in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: the role of endothelin-1 in the vascular dysregulation, 21 September 2022, PREPRINT (Version 1) available at Research Square https://doi.org/10.21203/rs.3.rs-2044838/v1 (Full text)

The higher resting heart rate in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) patients compared to healthy controls: relation with stroke volumes

Abstract:

Introduction: In patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) a higher-than-normal resting heart rate has been reported in a number of studies. As heart rate is linked to stroke volume, the present study explored the relationship between the supine heart rate and stroke volume index in healthy controls and in ME/CFS patients. Moreover, as patients with a postural orthostatic tachycardia syndrome (POTS) during tilt testing, have a higher supine heart rate than patients with a normal heart rate and blood pressure response during tilting, these two patient groups were also compared.

Methods and results: From a database of individuals who had undergone tilt-testing, including supine Doppler measurements for stroke volume index calculation, we selected ME/CFS patients and healthy controls without evidence of hypotension or syncope. 474 ME/CFS patients were analyzed, 314 with a normal heart rate and blood pressure response and 160 with POTS during tilt-testing, and 56 healthy controls. Resting stroke volume indices were similar between the 3 groups. All 3 groups had an inverse relation between the resting stroke volume index and resting heart rate (all p<0.0001). The slope of the relation was not significantly different between the 3 groups. Using the upper limit of the 95% prediction interval for the heart rate of healthy controls, 46 (15%) of patients with a normal heart rate and blood pressure response had a resting heart rate above the upper limit, 248 (85%) a heart rate between the upper and lower limit. In 47 (29%) patients developing POTS the resting heart rate was above the upper limit, and in 113 (71%) patients within the upper limit and lower limit. This distribution was significantly different between the two patient groups (p=0.0001).

Conclusion: Patients and healthy controls showed a significant and inverse relation between the SVI and heart rate at rest. Already at rest heart rate in patients developing POTS during tilt-testing were higher compared to the patients with a normal heart rate and blood pressure response per unit of SVI, but the heart rate of the majority of all patients fell within the limits of normal of healthy controls. The difference of patients with heart rate above the upper limit versus between the upper limit and lower limit deserves further investigation and may have therapeutic implications.

Source: VAN CAMPEN, C (Linda) M.C.; VISSER, Frans C.. The higher resting heart rate in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) patients compared to healthy controls: relation with stroke volumes.. Medical Research Archives, [S.l.], v. 10, n. 6, june 2022. ISSN 2375-1924. Available at: https://esmed.org/MRA/mra/article/view/2891. Date accessed: 17 july 2022. doi: https://doi.org/10.18103/mra.v10i6.2891.

Risk factors and multidimensional assessment of long COVID fatigue: a nested case-control study

Abstract:

Background: Fatigue is the most prevalent and debilitating long COVID symptom, however risk factors and pathophysiology of this condition remain unknown. We assessed risk factors for long COVID fatigue and explored its possible pathophysiology.

Methods: Nested case-control study in a COVID recovery clinic. Individuals with (cases) and without (controls) significant fatigue were included. We performed a multidimensional assessment evaluating various parameters, including pulmonary function tests and cardiopulmonary exercise testing, and implemented multivariable logistic regression to assess risk factors for significant long COVID fatigue.

Results: Total of 141 individuals were included. Mean age was 47 (SD 13) years; 115 (82%) were recovering from mild COVID-19. Mean time for evaluation was 8 months following COVID-19. Sixty-six (47%) individuals were classified with significant long COVID fatigue. They had significantly higher number of children, lower proportion of hypothyroidism, higher proportion of sore throat during acute illness and long COVID symptoms, and of physical limitation in daily activities. Individuals with fatigue had poorer sleep quality and higher degree of depression. They had significantly lower heart rate [153.52 (22.64) vs 163.52 (18.53), p=0.038] and oxygen consumption per Kg [27.69 (7.52) vs 30.71 (7.52), p=0.036] at peak exercise. The two independent risk factors for fatigue identified in multivariable analysis were peak exercise heart rate (odds ratio [OR] 0.79 per 10 beats/minute, 95% confidence interval [CI] 0.65-0.96, p=0.019); and long COVID memory impairment (OR 3.76, 95% CI 1.57-9.01, p=0.003).

Conclusions: Long COVID fatigue may be related to autonomic dysfunction, impaired cognition and decreased mood. This may suggest a limbic-vagal pathophysiology. Clinical Trial registration: NCT04851561.

Source: Margalit I, Yelin D, Sagi M, Rahat MM, Sheena L, Mizrahi N, Gordin Y, Agmon H, Epstein NK, Atamna A, Tishler O, Daitch V, Babich T, Abecasis D, Yarom Y, Kazum S, Shitenberg D, Baltaxe E, Elkana O, Shapira-Lichter I, Leibovici L, Yahav D. Risk factors and multidimensional assessment of long COVID fatigue: a nested case-control study. Clin Infect Dis. 2022 Apr 11:ciac283. doi: 10.1093/cid/ciac283. Epub ahead of print. PMID: 35403679.  https://pubmed.ncbi.nlm.nih.gov/35403679/