Investigating the Dose-Response Relationship between Deep Breathing and Heart Rate Variability in Healthy Participants and Across-Days Reliability in Patients with Rheumatoid Arthritis and Systemic Lupus Erythematosus

Abstract

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.

Keywords: breathing; deep breathing; dose-response; heart rate variability; inflammation; neuromodulation; reliability; rheumatoid arthritis; systemic lupus erythematosus; vagus nerve stimulation.

Figure 1

Bar chart showing the heart rate variability-parameters plotted as mean ± standard error in healthy participants. SDNN: The standard deviation of the R-R intervals. RMSSD: The root mean square of successive R-R intervals. PNN50: The proportion of NN50 (pairs of successive R-R intervals that differ more than 50 milliseconds) divided by the total number of R-R intervals. Post1, post2, and post3 were performed at 0–5, 12.5–17.5, and 25–30 min after the deep breathing intervention, respectively.

Figure 2

Bar chart showing the heart rate variability-parameters plotted as mean ± standard error in patients with RA and SLE. RA: Rheumatoid Arthritis. SLE: Systemic Lupus Erythematosus. SDNN: The standard deviation of the R-R intervals. RMSSD: The root mean square of successive R-R intervals. PNN50: The proportion of NN50 (pairs of successive R-R intervals that differ more than 50 milliseconds) divided by the total number of R-R intervals. Post1, post2, and post3 were performed at 0–5, 12.5–17.5, and 25–30 min after the deep breathing intervention, respectively.