Association between autonomic nerve activity and exercise-induced hypoxemia in COPD patients on long-term oxygen therapy

• Published in: Journal of respiratory physical therapy Vol. 4; no. 1; pp. 12 - 20
• Main Authors: 大場 健一郎, 川上 慧, 髙橋 精一郎
• Format: Journal Article
• Language: Japanese
• Published: Japanese Society of Respiratory Physical Therapy 21.03.2025; 一般社団法人 日本呼吸理学療法学会
• Subjects: COPD; 自律神経; 運動誘発性低酸素血症; 酸素療法
• ISSN: 2436-7966
• DOI: 10.51116/kokyurigakuryohogaku.4.1_12

Purpose: This study aimed to clarify the effects of exercise-induced hypoxemia (EIH) on autonomic nervous activity in patients with COPD using oxygenation.Patients and methods: Twenty-nine subjects with COPD who underwent pulmonary rehabilitation for at least 4 weeks and long-term oxygen therapy (LTOT) were enrolled in this study. Frequency analysis of heart rate variability was carried out from the electrocardiogram during the 6-minute walk test (6MWT), and low-frequency (LF) and high-frequency (HF) areas were extracted, with LF/HF as an index of sympathetic nerve activity and HF-normalized units (HFnu) as an index of parasympathetic nerve activity. Autonomic nervous activity, SpO2, and pulse rate during the 6MWT were averaged every 1 minute for changes in time series from rest to 3 minutes after walking, and comparisons were made between the two groups with EIH (EIH group) and without EIH (NOX group) during the 6MWT.Results: Autonomic nervous activity during walking was not significantly different between the two groups. LH/HF was significantly higher, and HFnu was significantly lower in the EIH group than in the NOX group at 1 and 3 minutes after walking. SpO2 showed significantly lower EIH 2 minutes after walking. Conclusion: EIH in patients with COPD using LTOT was found to have no effect on autonomic nervous activity during walking. EIH may affect the increase in sympathetic activity after walking, suggesting that the change in pulse rate and SpO2 during the 6MWT may be distinct from autonomic nervous activity.