Post-exertional Symptoms Are Similar In Male And Female Patients With Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome

Up to ninety percent of people affected by myalgic encephalomyelitis/ chronic fatigue syndrome (ME/CFS) remain undiagnosed. A hallmark feature of ME/CFS is post-exertional malaise (PEM), the worsening of symptoms following exertion. Men and women affected by the same disease may experience different symptoms, yet it is unknown whether PEM presents differently based on sex. PURPOSE: Compare PEM symptoms reported by males and females with ME/CFS after cardiopulmonary exercise testing (CPET). METHODS: During two maximal CPETs conducted 24 hours apart, ninety ME/CFS subjects (67 females, 23 males) described their symptoms via open-ended questionnaires at five different time points. Symptoms were then classified into 20 categories. Fisher's exact test was used to compare the percentages of men versus women endorsing each symptom category for each time point while the Mann-Whitney U test was used to compare the mean number of symptom categories reported and time needed to recover from the CPETs. A p < 0.05 was considered significant. RESULTS: During and following the CPETs, 25.6% more women reported gastrointestinal disturbances compared to men (34.3% vs. 8.7%, p = 0.02). Conversely, 24 hours after the first CPET, 15.7% more men reported light-headedness (21.7% vs. 6.0%, p = 0.04). Otherwise, men and women recounted similar symptoms. Immediately and 24 hours after the 2nd CPET, women endorsed slightly more symptom categories than men (3.5 ± 1.8 vs. 2.6 ± 1.5 and 3.7 ± 2.1 vs. 2.8 ± 1.7, respectively, both p = 0.04). Fifty-two percent of women and forty-five percent of men took more than a week to recover (p = 0.56). The remaining participants took 4.9 ± 2.1 days and 4.8 ± 1.8 days, respectively, to return to their baseline (p = 0.58). CONCLUSIONS: Except for gut symptoms and light-headedness, men and women with ME/CFS experienced similar symptoms during PEM. There were no differences in recovery time. Practitioners should ask about these two symptoms when attempting to identify PEM. Supported by: This study was supported by U54NS105541 awarded to Cornell University. A grant co-funded by the National Institutes of Neurological Disorders and Stroke, Allergy and Infectious Diseases, and Drug Abuse; National Heart, Lung, and Blood Institute; and National Human Genome Research Institute.