Functional somatic syndrome (FSS) includes a spectrum of somatic symptoms with insufficient medical explanation. Its underlying pathophysiology is considered to include dysfunctional stress-responsive systems or autonomic dysfunction. Among the autonomic dysfunction readouts, decreased heart rate variability (HRV) has been shown to be characteristic in patients with FSSs. However, its association with quality of life (QOL) has not been clearly examined. We examined the association between short-term resting HRV and QOL in patients with FSS (n = 47) and healthy controls (n = 28). The time domain parameters of HRV were mean heart rate per minute (HR), coefficient of variation of R–R intervals (CvRR) and root mean square of successive differences (RMSSD). The frequency domain parameters of HRV were low-frequency (LF) power and high-frequency (HF) power by power spectrum analysis. The Japanese version of the WHO’s QOL scale (WHOQOL-BREF) (WHO/QOL26) was used for the QOL assessment. There was a significant positive association between the RMSSD and HF power of HRV and all the QOL domains in patients with FSSs who had lower QOL scores on average than controls, while there was no association between HRV and any of the QOL domains in the control group. HF power was more dominantly associated with QOL than the other variables in patients with FSS based on the analysis with a multiple linear regression model. The present study elucidated that the HF power of HRV was dominantly associated with QOL in patients with FSSs who had lower QOL than controls. Vagal index of HRV could be a valuable indicator of the pathological condition and a significant predictor of health-related QOL in patients with FSSs.

功能性躯体综合征 (FSS) 包括一系列躯体症状，医学解释不充分。其潜在的病理生理学被认为包括功能失调的压力反应系统或自主神经功能障碍。在自主神经功能障碍读数中，心率变异性 (HRV) 降低已被证明是 FSS 患者的特征。然而，其与生活质量 (QOL) 的关联尚未得到明确研究。我们检查了 FSS 患者（n = 47）和健康对照组（n = 28）的短期静息 HRV 与 QOL 之间的关联。HRV的时域参数为平均每分钟心率（HR）、R-R间期变异系数（CvRR）和连续差均方根（RMSSD）。通过功率谱分析，HRV 的频域参数为低频（LF）功率和高频（HF）功率。使用日本版的 WHO 的 QOL 量表 (WHOQOL-BREF) (WHO/QOL26) 进行 QOL 评估。在平均 QOL 得分低于对照组的 FSS 患者中，RMSSD 和 HRV 的 HF 功率与所有 QOL 域之间存在显着的正相关，而 HRV 与对照组中的任何 QOL 域之间没有关联. 基于多元线性回归模型的分析，在 FSS 患者中，HF 功率与 QOL 的相关性比其他变量更显着。本研究阐明，在 QOL 低于对照组的 FSS 患者中，HRV 的 HF 功率与 QOL 显着相关。