Use of a breathing test for the differential diagnosis of autonomic dysfunction in children with sarcopenia

Abstract

Introduction. Sarcopenia in children is a poorly studied problem. Unlike adults, where sarcopenia is associated with aging, in children, it is primarily linked to comorbid conditions that cause muscle dystrophy. Sarcopenia is frequently accompanied by disorders of the autonomic nervous system (ANS), which regulates metabolism, circulation, and organ innervation, affecting muscle function. Such disorders can be considered autonomic dysfunction (AD), which manifests clinically as impairments in the cardiovascular, respiratory, or digestive systems due to an imbalance between sympathetic and parasympathetic regulation. Given the complex interplay between sarcopenia and autonomic dysfunction, it is crucial to identify reliable diagnostic methods that allow for differentiation between functional and pathological changes. The study aimed to determine the degree of suppression of the parasympathetic branch of the ANS in children and adolescents with sarcopenia and signs of autonomic dysfunction using a breathing test. Materials and methods. The study involved 22 children aged 10–13 years undergoing rehabilitation at the Zakarpattia Regional Children's Sanatorium "Malyatko." Sarcopenia was confirmed using bioimpedance analysis and dynamometry. Autonomic dysfunction was assessed based on heart rate variability (HRV) indicators obtained using the HRVscanner hardware-software complex. HRV was recorded in two modes: a standard 5-minute registration and a 1-minute registration under controlled diaphragmatic breathing (6 respiratory movements per minute). The breathing test aimed to evaluate the adaptability of the ANS by analyzing changes in HRV parameters in response to controlled breathing. Results. After the breathing test, 14 out of 22 examined children (63.6%) showed normalization of HRV indicators, indicating functional suppression of parasympathetic activity due to psychoemotional stress rather than an organic pathology. In contrast, in the remaining 8 cases (36.4%), no improvement in HRV parameters was observed, suggesting true autonomic dysfunction. These findings highlight the importance of distinguishing stress-induced functional changes from pathological autonomic impairments, as misclassification could lead to ineffective therapeutic interventions. Furthermore, the study underscores the role of non-invasive diagnostic tools such as HRV analysis and breathing testing in pediatric populations, offering valuable insights into the functional state of the ANS. Conclusions. The breathing test is an effective tool for differentiating functional changes in the ANS from pathological disturbances. This method provides a non-invasive, rapid, and reliable assessment of autonomic dysfunction in children with sarcopenia, which is crucial for developing targeted rehabilitation and therapeutic strategies. Early identification of ANS dysfunction in pediatric patients with sarcopenia enables timely intervention and personalized treatment plans, ultimately improving clinical outcomes and quality of life. Future research should focus on expanding the sample size and investigating long-term therapeutic strategies to manage autonomic dysfunction in children with sarcopenia.