Comparing Idiopathic Chronic Fatigue and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) in Males: Response to Two-Day Cardiopulmonary Exercise Testing Protocol

Abstract:

(1) Introduction: Multiple studies have shown that peak oxygen consumption is reduced in the majority of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS )patients, using the gold standard for measuring exercise intolerance: cardiopulmonary exercise testing (CPET). A 2-day CPET protocol has shown different results on day 2 in ME/CFS patients compared to sedentary controls. No comparison is known between ME/CFS and idiopathic chronic fatigue (ICF) for 2-day CPET protocols. We compared ME/CFS patients with patients with chronic fatigue who did not fulfill the ME/CFS criteria in a male population and hypothesized a different pattern of response would be present during the 2nd day CPET.

(2) Methods: We compared 25 male patients with ICF who had completed a 2-day CPET protocol to an age-/gender-matched group of 26 male ME/CFS patients. Measures of oxygen consumption (VO2), heart rate (HR), systolic and diastolic blood pressure, workload (Work), and respiratory exchange ratio (RER) were collected at maximal (peak) and ventilatory threshold (VT) intensities.

(3) Results: Baseline characteristics for both groups were similar for age, body mass index (BMI), body surface area, (BSA), and disease duration. A significant difference was present in the number of patients with fibromyalgia (seven ME/CFS patients vs. zero ICF patients). Heart rate at rest and the RER did not differ significantly between CPET 1 and CPET 2. All other CPET parameters at the ventilatory threshold and maximum exercise differed significantly (p-value between 0.002 and <0.0001). ME/CFS patients showed a deterioration of performance on CPET2 as reflected by VO2 and workload at peak exercise and ventilatory threshold, whereas ICF patients showed improved performance on CPET2 with no significant change in peak workload.

(4) Conclusion: This study confirms that male ME/CFS patients have a reduction in exercise capacity in response to a second-day CPET. These results are similar to published results in male ME/CFS populations. Patients diagnosed with ICF show a different response on day 2, more similar to sedentary and healthy controls.

Source: van Campen CLMC, Visser FC. Comparing Idiopathic Chronic Fatigue and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) in Males: Response to Two-Day Cardiopulmonary Exercise Testing Protocol. Healthcare (Basel). 2021 Jun 5;9(6):683. doi: 10.3390/healthcare9060683. PMID: 34198946. https://pubmed.ncbi.nlm.nih.gov/34198946/

Female Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome or Idiopathic Chronic Fatigue: Comparison of Responses to a Two-Day Cardiopulmonary Exercise Testing Protocol

Abstract:

Introduction: Multiple studies have shown that peak oxygen consumption is reduced in the majority of ME/CFS patients, using the golden standard for measuring exercise intolerance: cardiopulmonary exercise testing (CPET). A 2-day CPET protocol has shown different results on day 2 in ME/CFS patients compared to sedentary controls. No comparison is known between ME/CFS and idiopathic chronic fatigue (ICF) for 2-day CPET protocols. We compared ME/CFS patients with patients with chronic fatigue who did not fulfil the ME/CFS criteria in a male population and hypothesized a different pattern of response would be present during the 2nd day CPET.

Methods: Fifty-one female patients with ICF completed a 2-day CPET protocol and were compared to an age/sex-matched group of 50 female ME/CFS patients. Measures of oxygen consumption (VO2), heart rate (HR), systolic and diastolic blood pressure, workload (Work), and respiratory exchange ratio (RER) were collected at maximal (peak) and ventilatory threshold (VT) intensities.

Results: Baseline characteristics for both groups were similar for age, BMI, BSA, and disease duration. A significance difference was present in the number of patients with fibromyalgia (seven ME/CFS patients vs zero ICF patients). Heart rate at rest and the RER did not differ significantly between CPET 1 and CPET 2. All other CPET parameters at the ventilatory threshold and maximum exercise differed significantly (p-value between 0.002 and <0.0001). ME/CFS patients showed a deterioration of performance on CPET2 as reflected by VO2 and workload at peak exercise and ventilatory threshold, whereas ICF patients showed improved performance on CPET2 with no significant change in peak workload.

Conclusion: This study confirms that female ME/CFS patients have a reduction in exercise capacity in response to a second day CPET. These results are similar to published results in female ME/CFS populations. Patients diagnosed with ICF show a different response on day 2, more similar to sedentary and healthy controls.

Source: van Campen CLMC, Visser FC. Female Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome or Idiopathic Chronic Fatigue: Comparison of Responses to a Two-Day Cardiopulmonary Exercise Testing Protocol. Healthcare (Basel). 2021 Jun 5;9(6):682. doi: 10.3390/healthcare9060682. PMID: 34198913. https://pubmed.ncbi.nlm.nih.gov/34198913/

Oxidative Stress is a Convincing Contributor to Idiopathic Chronic Fatigue

Abstract:

The linkage between oxidative stress and idiopathic chronic fatigue (ICF) has not been explored in detail. This study thoroughly compared the serum levels of biomarkers for oxidative stress and antioxidants from 103 subjects with ICF (20 men and 83 women) to those of 82 healthy volunteers (27 men and 55 women).

Oxidative parameters, which included reactive oxygen species (ROS), malondialdehyde (MDA) and F2-isoprotan, and tumor necrosis factor-alpha (TNF-α) were significantly elevated, while antioxidant parameters, which included total antioxidant activity (TAC), catalase, superoxide dismutase, SOD and GSH activity, were decreased compared to those of healthy subjects (by approximately 1.2- to 2.3-fold, p < 0.05 or 0.01).

Our results confirmed that oxidative stress is a key contributor in the pathophysiology of ICF, and firstly explored the features of oxidative stress parameters in ICF subjects compared to a healthy population.

Source: Lee JS, Kim HG, Lee DS, Son CG. Oxidative Stress is a Convincing Contributor to Idiopathic Chronic Fatigue. Sci Rep. 2018;8(1):12890. Published 2018 Aug 27. doi:10.1038/s41598-018-31270-3 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6110864/ (Full article)