Two-Day Cardiopulmonary Exercise Testing in Long COVID Post-Exertional Malaise Diagnosis

Abstract:

Background: Long COVID patients present with a myriad of symptoms that can include fatigue, exercise intolerance and post exertional malaise (PEM). Long COVID has been compared to other post viral syndromes, including myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), where a reduction in day 2 cardiopulmonary exercise test (CPET) performance of a two-day CPET protocol is suggested to be a result of PEM. We investigated cardiopulmonary and perceptual responses to a two-day CPET protocol in Long COVID patients.

Methods: 15 Long COVID patients [n=7 females; mean (SD) age: 53(11) yr; BMI = 32.2(8.5) kg/m2] performed a pulmonary function test and two ramp-incremental CPETs separated by 24hr. CPET variables included gas exchange threshold (GET), V̇O2peak and WRpeak. Ratings of perceived dyspnoea and leg effort were recorded at peak exercise using the modified 0-10 Borg Scale. PEM (past six months) was assessed using the modified DePaul Symptom Questionnaire (mDSQ). One-sample t-tests were used to test significance of mean difference between days (p<0.05).

Results: mDSQ revealed PEM in 80% of patients. Lung function was normal. Responses to day 1 CPET were consistent with the presence of aerobic deconditioning in 40% of patients (V̇O2peak <80% predicted, in the absence of evidence of cardiovascular and pulmonary limitations). There were no differences between day-1 and day-2 CPET responses (all p>0.05).

Conclusion: Post exertional malaise symptoms in Long COVID patients, in the absence of differences in two-day CPET responses separated by 24hours, suggests that post-exertional malaise is not due to impaired recovery of exercise capacity between days.

Source: Gattoni C, Abbasi A, Ferguson C, Lanks CW, Decato TW, Rossiter HB, Casaburi R, Stringer WW. Two-Day Cardiopulmonary Exercise Testing in Long COVID Post-Exertional Malaise Diagnosis. Respir Physiol Neurobiol. 2024 Oct 25:104362. doi: 10.1016/j.resp.2024.104362. Epub ahead of print. PMID: 39490617. https://www.sciencedirect.com/science/article/pii/S1569904824001551 (Full text)

Attenuating Post-exertional Malaise in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Long-COVID: Is Blood Lactate Monitoring the Answer?

Highlights:

  • Lactate monitoring has the potential to extend beyond applied sports settings and could be used to monitor the physiologic and pathophysiological responses to external and internal stimuli in chronic disease areas such as Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Post-Covid syndrome or Long Covid.
  • It is applicable due to the recurrent, episodic and often disabling post-exertional symptom exacerbation (PESE) otherwise referred to as post-exertional malaise (PEM) which is a characteristic symptom of ME/CFS and Long Covid that can last for days and/or weeks.
  • Lactate monitoring presents an opportunity to support those living with ME/CFS and Long COVID, by allowing patients and practitioners to determine the intensity and anaerobic contribution to everyday tasks which could aid the development of pacing strategies that prevent PEM/PESE.

Source: Faghy PMA, Ashton DRE, McNeils MR, Arena R, Duncan DR. Attenuating Post-exertional Malaise in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Long-COVID: Is Blood Lactate Monitoring the Answer? Curr Probl Cardiol. 2024 Mar 30:102554. doi: 10.1016/j.cpcardiol.2024.102554. Epub ahead of print. PMID: 38561114. https://www.sciencedirect.com/science/article/abs/pii/S0146280624001932

Focus on Post-Exertional Malaise when approaching ME/CFS in specialist healthcare improves satisfaction and reduces deteriorations

Abstract:

Background: Post-Exertional Malaise (PEM) is considered a hallmark characteristic of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). This may also apply to subgroups of patients with long COVID induced ME/CFS. However, it is uncertain to what extent PEM is acknowledged in routine specialist healthcare for ME/CFS patients, and how this affects patient outcomes.

Objective: This study aims to evaluate to what extent ME/CFS patients experienced focus on PEM in specialist healthcare practice and its significance for outcome and care quality.

Methods: Data from two online cross-sectional surveys covering specialist healthcare services for ME/CFS patients at rehabilitation institutes in Norway and at two regional hospitals respectively, were analyzed. Evaluations of 788 rehabilitation stays, 86 hospital consultations and 89 hospital interventions were included.

Logistic regression models and Mann-Whitney U tests were used to quantify the impact of addressing PEM on health and functioning, care satisfaction or benefit. Spearman’s rank correlation and Cronbach’s alpha of focus on PEM with the respondents’ perception of healthcare providers’ knowledge, symptom acknowledgement and suitability of intervention were assessed as measures for care quality and their internal consistency, respectively.

Results: PEM was addressed in 48% of the rehabilitation stays, 43% of the consultations and 65% of the hospital interventions. Failure to address PEM roughly doubled the risk of health deterioration following rehabilitation (OR=0.39, 95%CI 0.29-0.52; 40.1% vs 63.2% P= <.001) and hospital intervention (OR=0.34, 95%CI 0.13-0.89; 22.4% vs. 45.2%, P=.026).

PEM-focus during the clinical contact was associated with significantly higher scores on patients’ rated care satisfaction and benefit of both consultation and intervention. Furthermore, addressing PEM was (inter)related to positive views about healthcare providers’ level of knowledge of ME/CFS, their acknowledgment of symptoms, obtained knowledge, and the perceived suitability of intervention (Cronbach’s alpha ≥ 0.80).

Conclusion: PEM is still frequently not acknowledged in specialist healthcare practice for ME/CFS patients in Norway. Not addressing PEM substantially increased the probability of a decline in health and functioning following intervention and was strongly associated with reduced perceived care quality, satisfaction and benefit. These findings may be related to the applied explanatory models for ME/CFS and are most likely of relevance to long COVID.

Source: Marjon E. Wormgoor, Sanne C. Rodenburg. Focus on Post-Exertional Malaise when approaching ME/CFS in specialist healthcare improves satisfaction and reduces deteriorations. Frontiers in Neurology 14- 2023. https://www.frontiersin.org/articles/10.3389/fneur.2023.1247698/abstract

Home-based testing protocol to measure physiological responses to everyday activities in ME: a feasibility study

Abstract:

Background and objectives: Individuals with Myalgic Encephalomyelitis (ME) have shown altered physiological responses during maximum cardiopulmonary exercise testing. However, maximal testing is not representative of the everyday activities reported to cause or increase symptoms in ME, and is not accessible for those with severe or very severe illness. The aim of this study was to assess the feasibility and acceptability of a home-based testing protocol to measure physiological responses in ME to everyday activity.

Methods: Researchers attended participants’ homes to collect data and provide equipment for independent testing. Adults with ME who met the International Consensus Criteria wore a portable metabolic assessment system and a physiological stress monitor. Blood pressure, heart rate, oxygen saturation and lactic acid were assessed during a range of everyday positions and activities in their own homes.

Results: Online recruitment yielded 70 volunteers in 24 h. 17 eligible individuals reflecting a range of illness severities were enrolled. All participants found the procedures acceptable with 12 (70%) subjects completing every listed activity. Apparent physiological abnormalities were identified in all participants.

Conclusion: Physiological measurement during everyday activities was feasible for our participants who represented a range of ME severities. Activities must be adapted for different levels of severity to avoid significant symptom exacerbation. Further research is needed to develop home-based assessment protocols to advance the biobehavioral understanding of ME.

Trial registration number: ISRCTN78379409

Source: Nicola Clague-Baker, Sarah Tyson, Karen Leslie, Helen Dawes, Michelle Bull & Natalie Hilliard (2023) Home-based testing protocol to measure physiological responses to everyday activities in ME: a feasibility study, Fatigue: Biomedicine, Health & Behavior, DOI: 10.1080/21641846.2023.2245584 https://www.tandfonline.com/doi/full/10.1080/21641846.2023.2245584 (Full text)

An Exercise Immune Fitness test to unravel mechanisms of post-acute sequelae of COVID-19

Abstract:

The Post-Acute Sequelae of COVID-19 (PASC) Syndrome is a debilitating syndrome with onset three months post COVID-19 infection, marked by the presence of fatigue, headache, cognitive dysfunction, post-exertional malaise, orthostatic intolerance, and dyspnea that is clinically relevant and is at least as severe as fatigue in several other clinical conditions, including cancer. The onset, progression, and symptom profile of PASC patients have considerable overlap with Myalgic-Encephalopathy/Chronic Fatigue Syndrome (ME/CFS).

In people with ME/CFS, exercise (and other types of exertion) can cause serious setbacks and deterioration in function. Post-exertional malaise (PEM) appears to be a common and a significant challenge for the majority of this patient group. Of the nearly 24 million adults in the U.S. who currently have long COVID, more than 80% are having some trouble carrying out daily activities. Mechanisms of PACS remain poorly understood.

While multi-omic information gathered at the time of acute COVID-19 onset may help predict long COVID outcomes, we here propose to test the hypothesis that additional molecular immunological information collected during standardized exercise-testing for cardio-respiratory fitness after recovery from acute COVID-19 can be used to improve the understanding of mechanisms of PASC.

Source: Deng MC. An Exercise Immune Fitness test to unravel mechanisms of post-acute sequelae of COVID-19. Expert Rev Clin Immunol. 2023 May 16. doi: 10.1080/1744666X.2023.2214364. Epub ahead of print. PMID: 37190994. https://www.tandfonline.com/doi/full/10.1080/1744666X.2023.2214364 (Full text)

Development and measurement properties of the PEM/PESE activity questionnaire (PAQ)

Abstract:

Background: Existing instruments often are inappropriate to measure the effects of post-exertional malaise (PEM) and post-exertional symptom exacerbation (PESE) on activities of daily living (ADLs). A validated questionnaire to measure self-reported ability with ADLs would advance research and clinical practice in conditions like myalgic encephalomyelitis and Long Covid.

Objective: Determine the measurement properties of the PEM/PESE Activity Questionnaire (PAQ).

Methods: The PAQ is adapted from the Patient Specific Functional Scale. Respondents rated three self-selected ADLs on two 0-100 scales, including current performance compared to (1) a ‘good day’ and (2) before illness. Respondents provided a Burden of Functioning rating on a 0-100 scale, anchored at 0 being the activity took “No time, effort, and resources at all” and 10 being “All of my time, effort, and resources.” Respondents took the PAQ twice, completing a demographic questionnaire after the first PAQ and before the second PAQ. Descriptive statistics and intraclass correlation coefficients were calculated for each scale to assess test-retest reliability. Minimum detectable change outside the 95% confidence interval (MDC95) was calculated. Ceiling and floor effects were determined when the MDC95 for average and function scores crossed 0 and 100, respectively.

Results: n = 981 responses were recorded, including n = 675 complete surveys. Test-retest reliability was generally fair to excellent, depending on function and scale. MDC95 values generally indicated scale responsiveness. Ceiling and floor effects were noted infrequently for specific functions.

Conclusion: The PAQ is valid, reliable, and sensitive. Additional research may explore measurement properties involving functions that were infrequently selected in this sample.

Source: Davenport TE, Stevens SR, Stevens J, Snell CR, Van Ness JM. Development and measurement properties of the PEM/PESE activity questionnaire (PAQ). Work. 2023 Mar 13. doi: 10.3233/WOR-220553. Epub ahead of print. PMID: 36938768. https://content.iospress.com/articles/work/wor220553 (Full text)

Two symptoms can accurately identify post-exertional malaise in myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

Background: Post-exertional malaise (PEM) is the hallmark symptom of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) yet its diverse manifestations make it difficult to recognize. Brief instruments for detecting PEM are critical for clinical and scientific progress.

Objective: To develop a clinical prediction rule for PEM.

Method: 49 ME/CFS and 10 healthy, sedentary subjects recruited from the community completed two maximal cardiopulmonary exercise tests (CPETs) separated by 24 hours.

At five different times, subjects reported symptoms which were then classified into 19 categories. The frequency of symptom reports between groups at each time point was compared using Fisher’s exact test.

Receiver operating characteristics (ROC) analysis with area under the curve calculation was used to determine the number of different types of symptom reports that were sufficient to differentiate between ME/CFS and sedentary groups. The optimal number of symptoms was determined where sensitivity and specificity of the types of symptom reports were balanced.

Results: At all timepoints, a maximum of two symptoms was optimal to determine differences between groups. Only one symptom was necessary to optimally differentiate between groups at one week following the second CPET. Fatigue, cognitive dysfunction, lack of positive feelings/mood and decrease in function were consistent predictors of ME/CFS group membership across timepoints.

Conclusion: Inquiring about post-exertional cognitive dysfunction, decline in function, and lack of positive feelings/mood may help identify PEM quickly and accurately. These findings should be validated with a larger sample of patients.

Source: Davenport, Todd E; Chu, Lily; Stevens, Staci R; Stevens, Jared; Snell, Christopher R; Van Ness, J. Mark. Two symptoms can accurately identify post-exertional malaise in myalgic encephalomyelitis/chronic fatigue syndrome. Work. 1 Jan. 2023 : 1 – 15. https://content.iospress.com/articles/work/wor220554 (Full text)

Diminished Cardiopulmonary Capacity During Post-Exertional Malaise

Reduced functional capacity and post-exertional malaise following physical activity are hallmark symptoms of Chronic Fatigue Syndrome (CFS). That these symptoms are often delayed may explain the equivocal results for clinical cardiopulmonary exercise testing with CFS patients. The reproducibility of VO2 max in healthy subjects is well documented. This may not be the case with CFS due to delayed recovery symptoms.

Purpose: To compare results from repeated exercise tests as indicators of post-exertional malaise in CFS.

Methods: Peak oxygen consumption (VO2 peak), percentage of predicted peak heart rate (HR%), and VO2 at anaerobic threshold (AT), were compared between six CFS patients and six control subjects for two maximal exercise tests separated by 24 hours.

Results: Multivariate analysis showed no significant differences between control and CFS, respectively, for test 1: VO2 peak (28.4 ± 7.2 ml/ kg/min; 26.2 ± 4.9 ml/kg/min), AT (17.5 ± 4.8 ml/kg/min; 15.0 ± 4.9 ml/ kg/min) or HR% (87.0 ± 25.4%; 94.8 ± 8.8%). However, for test 2 the CFS patients achieved significantly lower values for both VO2 peak (28.9 ± 8.0 ml/kg/min; 20.5 ± 1.8 ml/kg/min, p = 0.031) and AT (18.0 ± 5.2 ml/kg/min; 11.0 ± 3.4 ml/kg/min, p = 0.021). HR% was not significantly different (97.6 ± 27.2%; 87.8 ± 9.3%, p = 0.07). A follow-up classification analysis differentiated between CFS patients and controls with an overall accuracy of 92%.

Conclusion: In the absence of a second exercise test, the lack of any significant differences for the first test would appear to suggest no functional impairment in CFS patients. However, the results from the second test indicate the presence of a CFS related post-exertional malaise. It might be concluded then that a single exercise test is insufficient to demonstrate functional impairment in CFS patients. A second test may be necessary to document the atypical recovery response and protracted malaise unique to CFS.

Source: J. Mark Vanness, Christopher R. Snell & Staci R. Stevens (2007) Diminished Cardiopulmonary Capacity During Post-Exertional Malaise, Journal of Chronic Fatigue Syndrome, 14:2, 77-85, DOI: 10.1300/J092v14n02_07

Differential Effects of Exercise on fMRI of the Midbrain Ascending Arousal Network Nuclei in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Gulf War Illness (GWI) in a Model of Postexertional Malaise (PEM)

Abstract:

Background: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), Gulf War Illness (GWI) and control subjects underwent fMRI during difficult cognitive tests performed before and after submaximal exercise provocation (Washington 2020). Exercise caused increased activation in ME/CFS but decreased activation for GWI in the dorsal midbrain, left Rolandic operculum and right middle insula. Midbrain and isthmus nuclei participate in threat assessment, attention, cognition, mood, pain, sleep, and autonomic dysfunction.

Methods: Activated midbrain nuclei were inferred by a re-analysis of data from 31 control, 36 ME/CFS and 78 GWI subjects using a seed region approach and the Harvard Ascending Arousal Network.

Results: Before exercise, control and GWI subjects showed greater activation during cognition than ME/CFS in the left pedunculotegmental nucleus. Post exercise, ME/CFS subjects showed greater activation than GWI ones for midline periaqueductal gray, dorsal and median raphe, and right midbrain reticular formation, parabrachial complex and locus coeruleus. The change between days (delta) was positive for ME/CFS but negative for GWI, indicating reciprocal patterns of activation. The controls had no changes.

Conclusions: Exercise caused the opposite effects with increased activation in ME/CFS but decreased activation in GWI, indicating different pathophysiological responses to exertion and mechanisms of disease. Midbrain and isthmus nuclei contribute to postexertional malaise in ME/CFS and GWI.

Source: Baraniuk JN, Amar A, Pepermitwala H, Washington SD. Differential Effects of Exercise on fMRI of the Midbrain Ascending Arousal Network Nuclei in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Gulf War Illness (GWI) in a Model of Postexertional Malaise (PEM). Brain Sci. 2022 Jan 5;12(1):78. doi: 10.3390/brainsci12010078. PMID: 35053821. https://pubmed.ncbi.nlm.nih.gov/35053821/

Submaximal Exercise Provokes Increased Activation of the Anterior Default Mode Network During the Resting State as a Biomarker of Postexertional Malaise in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

Background: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is characterized by disabling fatigue and postexertional malaise. We developed a provocation paradigm with two submaximal bicycle exercise stress tests on consecutive days bracketed by magnetic resonance imaging, orthostatic intolerance, and symptom assessments before and after exercise in order to induce objective changes of exercise induced symptom exacerbation and cognitive dysfunction.

Method: Blood oxygenation level dependent (BOLD) scans were performed while at rest on the preexercise and postexercise days in 34 ME/CFS and 24 control subjects. Seed regions from the FSL data library with significant BOLD signals were nodes that clustered into networks using independent component analysis. Differences in signal amplitudes between groups on pre- and post-exercise days were determined by general linear model and ANOVA.

Results: The most striking exercise-induced effect in ME/CFS was the increased spontaneous activity in the medial prefrontal cortex that is the anterior node of the Default Mode Network (DMN). In contrast, this region had decreased activation for controls. Overall, controls had higher BOLD signals suggesting reduced global cerebral blood flow in ME/CFS.

Conclusion: The dynamic increase in activation of the anterior DMN node after exercise may be a biomarker of postexertional malaise and symptom exacerbation in CFS. The specificity of this postexertional finding in ME/CFS can now be assessed by comparison to post-COVID fatigue, Gulf War Illness, fibromyalgia, chronic idiopathic fatigue, and fatigue in systemic medical and psychiatric diseases.

Source: Rayhan RU, Baraniuk JN. Submaximal Exercise Provokes Increased Activation of the Anterior Default Mode Network During the Resting State as a Biomarker of Postexertional Malaise in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Front Neurosci. 2021 Dec 15;15:748426. doi: 10.3389/fnins.2021.748426. PMID: 34975370; PMCID: PMC8714840. https://www.frontiersin.org/articles/10.3389/fnins.2021.748426/full  (Full text)