Cardiac output and arteriovenous oxygen difference contribute to lower peak oxygen uptake in patients with fibromyalgia

Abstract

Background Patients with fibromyalgia (FM) exhibit low peak oxygen uptake ($$\dot{\text{V}}$$ V ˙ O2peak). We aimed to detect the contribution of cardiac output to ($$\dot{\text{Q}}$$ Q ˙ ) and arteriovenous oxygen difference $$[\text{C}(\text{a-v})\text{O}_{2}]$$ [ C ( a-v ) O 2 ] to $$\dot{\text{V}}\text{O}_{2}$$ V ˙ O 2 from rest to peak exercise in patients with FM. Methods Thirty-five women with FM, aged 23 to 65 years, and 23 healthy controls performed a step incremental cycle ergometer test until volitional fatigue. Alveolar gas exchange and pulmonary ventilation were measured breath-by-breath and adjusted for fat-free body mass (FFM) where appropriate. $$\dot{\text{Q}}$$ Q ˙ (impedance cardiography) was monitored. $$\text{C}(\text{a-v})\text{O}_{2}$$ C ( a-v ) O 2 was calculated using Fick’s equation. Linear regression slopes for oxygen cost (∆$$\dot{\text{V}}$$ V ˙ O2/∆work rate) and $$\dot{\text{Q}}$$ Q ˙ to $$\text{V}$$ V O2 (∆$$\dot{\text{Q}}$$ Q ˙ /∆$$\dot{\text{V}}$$ V ˙ O2) were calculated. Normally distributed data were reported as mean ± SD and non-normal data as median [interquartile range]. Results $$\dot{\text{V}}$$ V ˙ O2peak was lower in FM patients than in controls (22.2 ± 5.1 vs. 31.1 ± 7.9 mL∙min−1∙kg−1, P < 0.001; 35.7 ± 7.1 vs. 44.0 ± 8.6 mL∙min−1∙kg FFM−1, P < 0.001). $$\dot{\text{Q}}$$ Q ˙ and C(a-v)O2 were similar between groups at submaximal work rates, but peak $$\dot{\text{Q}}$$ Q ˙ (14.17 [13.34–16.03] vs. 16.06 [15.24–16.99] L∙min−1, P = 0.005) and C(a-v)O2 (11.6 ± 2.7 vs. 13.3 ± 3.1 mL O2∙100 mL blood−1, P = 0.031) were lower in the FM group. No significant group differences emerged in ∆$$\dot{\text{V}}$$ V ˙ O2/∆work rate (11.1 vs. 10.8 mL∙min−1∙W−1, P = 0.248) or ∆$$\dot{\text{Q}}$$ Q ˙ /∆$$\dot{\text{V}}$$ V ˙ O2 (6.58 vs. 5.75, P = 0.122) slopes. Conclusions Both $$\dot{\text{Q}}$$ Q ˙ and C(a-v)O2 contribute to lower $$\dot{\text{V}}$$ V ˙ O2peak in FM. The exercise responses were normal and not suggestive of a muscle metabolism pathology. Trial registration ClinicalTrials.gov, NCT03300635. Registered 3 October 2017—Retrospectively registered. https://clinicaltrials.gov/ct2/show/NCT03300635.

Comparative Analysis of Ventilatory Responses during Stress Tests in Patients with Chronic Pain: Implications for Therapeutic Interventions

“…Lehto et al conducted a study to determine the differences in the cardiac and ventilatory variables during exercise with 35 patients diagnosed with FM and 23 women as the control group, concluding that the exercise responses were normal and not suggestive of muscle metabolism pathology. Moreover, the VO2 peak and cardiography impedance were lower in the FM group, indicating a possible influence of exercise on physiological responses [ 33 ].…”

“…Additionally, the literature has reported differences in the mitochondrial function and oxidative capacity of muscle cells, which could have contributed to the observed anaerobic endurance differences [ 35 , 36 ]. Fibromyalgia patients might have enhanced mitochondrial efficiency, allowing for prolonged aerobic energy production before transitioning to anaerobic metabolism [ 33 , 37 ]. The anaerobic differences observed in this experiment could also be related to pain perception and tolerance, which are remarkable characteristics of FM.…”

Machine learning identifies fatigue as a key symptom of fibromyalgia reflected in tyrosine, purine, pyrimidine, and glutaminergic metabolism

“…The study design and data acquisition have previously been described in detail 9–12 . In brief, the study cohort comprised 54 female patients with fibromyalgia, aged 18–65 years, from Helsinki University Hospital outpatient clinics, City of Vantaa primary health care, and the private clinic of one of the authors (R.M.).…”

“…The study design and data acquisition have previously been described in detail. 9 , 10 , 11 , 12 In brief, the study cohort comprised 54 female patients with fibromyalgia, aged 18–65 years, from Helsinki University Hospital outpatient clinics, City of Vantaa primary health care, and the private clinic of one of the authors (R.M.). Thirty‐one age‐matched female controls were recruited from the staff of these health care units and a local home economics organization (Uudenmaan Martat ry).…”

“…The study design and data acquisition have previously been described in detail. [9][10][11][12] In brief, the study cohort comprised 54 female patients with fibromyalgia, aged 18-65 years, from Helsinki University Hospital outpatient including changes in metabolism. However, it remains unclear what are the contributions of individual symptoms to fibromyalgia symptom burden, what metabolic changes are relevant for fibromyalgia, and whether different metabolic anomalies could be linked to individual symptoms of fibromyalgia.…”