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.

Modulating Heart Rate Variability through Deep Breathing Exercises and Transcutaneous Auricular Vagus Nerve Stimulation: A Study in Healthy Participants and in Patients with Rheumatoid Arthritis or Systemic Lupus Erythematosus

“…In the patient population, both interventions increased the HRV parameters significantly, and the effects of taVNS and DB were not significantly different. In line with our results, it has previously been shown that one session of 30 min of DB significantly increased HRV parameters in patients with RA and SLE [ 36 , 37 ]. In the current study, the measurements were continued for up to 30 min after intervention, and at this time point, the HRV parameters were still significantly increased compared to the baseline.…”

“…This could indicate that an effect can be achieved in less than 30 min. This was also supported in a recent study, but it was shown that a larger effect was obtained when increasing the duration of DB from 5 to 30 min [ 37 ]. Previous studies on taVNS mainly used a stimulation period shorter than 30 min.…”

“…The DB exercises were based on a procedure described in previous studies [ 33 , 36 , 37 , 45 ], and they consisted of 4 s of inspiration and 6 s of expiration with a total duration of 30 min. Initially, participants received verbal instructions, and during the exercise, they were guided by a visual cue.…”

“…Another way to stimulate the VN is through deep breathing (DB) exercises [ 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 ]. The mechanisms through which DB stimulates the VN are not well established, but are believed to include peripheral factors, such as the baroreflex, the peripheral chemoreflex, the Bainbridge reflex, and the Heuring–Breuer reflex, as well as such central elements as the respiratory and cardiovascular centers in the brainstem [ 38 ].…”

“…Most of the studies that have investigated DB tested the effect on HRV, and even though the methods of DB exercises used in these studies vary distinctively, a general increase in HRV parameters was found. Only two studies investigated the effect of DB in patients with RA and SLE, where DB increased the HRV parameters [ 36 , 37 ]. Furthermore, Twal et al found that yogic DB can decrease cytokine levels in saliva in healthy participants [ 32 ].…”