Background/ObjectiveAutoimmune diseases such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) have been associated with an impaired function of the autonomic nervous system and reduced vagus nerve (VN) tone measured through lower heart rate variability (HRV). Targeting the VN through electrical stimulation has been proposed as a treatment strategy with promising results in patients with RA. Moreover, it has been suggested that the VN can be stimulated physiologically through deep breathing. In this study, the aim was to investigate if the VN can be stimulated through deep breathing in patients with RA and SLE, as measured by HRV.MethodsFifty-seven patients with RA and SLE performed deep breathing exercises for 30 minutes in this explorative study. Before the breathing exercise, 2 electrocardiogram recordings were obtained to determine the patient's baseline HRV during rest. After the 30-minute breathing exercise, 5 minutes of electrocardiogram recordings were obtained to determine postintervention HRV and used as a measure of vagal activity.ResultsNo change was observed in the HRV between the 2 recordings prior the exercise, but the heart rate and HRV significantly decreased and increased, respectively, after the deep breathing exercise.ConclusionsHRV can be modulated in patients with RA and SLE; this may have implications for future treatment with medications in conjunction with deep breathing. However, the biological and clinical effect of deep breathing must be investigated in future studies.

Rheumatoid Arthritis (RA) and Systemic Lupus Erythematosus (SLE) are associated with autonomic dysfunction, potentially through reduced vagus nerve tone. Vagus nerve stimulation has been proposed as an anti-inflammatory treatment, and it can be performed through deep breathing (DB) exercises. In this study, the dose-response relationship between DB exercises and heart rate variability (HRV) was investigated in healthy participants and reliability across days in patients with RA and SLE. On three separate days, 41 healthy participants performed DB for: 5, 15, or 30 min. On two separate days, 52 RA or SLE patients performed DB with the dose associated with the highest HRV increase in healthy participants. The HRV was estimated from ECG-recordings recorded prior and post the DB exercises. Increases in dose led to larger HRV-responses. Thirty minutes led to the largest HRV-response. In the RA and SLE patients, this dose increased the HRV-parameters consistently across the two days, indicating reliability. DB increases HRV in healthy participants and RA or SLE patients, which indicates stimulation of the vagus nerve. Of the tested durations, 30 min of DB was the optimal period of stimulation. A potential anti-inflammatory effect of DB exercises should be investigated in future studies.

Rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) are associated with an impaired autonomic nervous system and vagus nerve function. Electrical or physiological (deep breathing—DB) vagus nerve stimulation (VNS) could be a potential treatment approach, but no direct comparison has been made. In this study, the effect of transcutaneous auricular VNS (taVNS) and DB on vagal tone was compared in healthy participants and RA or SLE patients. The vagal tone was estimated using time-domain heart-rate variability (HRV) parameters. Forty-two healthy participants and 52 patients performed 30 min of DB and 30 min of taVNS on separate days. HRV was recorded before and immediately after each intervention. For the healthy participants, all HRV parameters increased after DB (SDNN + RMSSD: 21–46%), while one HRV parameter increased after taVNS (SDNN: 16%). For the patients, all HRV parameters increased after both DB (17–31%) and taVNS (18–25%), with no differences between the two types of VNS. DB was associated with the largest elevation of the HRV parameters in healthy participants, while both types of VNS led to elevated HRV parameters in the patients. The findings support a potential use of VNS as a new treatment approach, but the clinical effects need to be investigated in future studies.