Exploratory analysis of spontaneous versus paced breathing on heart rate variability in veterans with combat-related traumatic injury

Rabeea Maqsood; Susie Schofield; Alexander N Bennett; Ahmed Khattab; Anthony M J Bull; Nicola T Fear; Christopher J Boos; ADVANCE Study

doi:10.1002/pmrj.13164

Exploratory analysis of spontaneous versus paced breathing on heart rate variability in veterans with combat-related traumatic injury

PM R. 2024 Apr 18. doi: 10.1002/pmrj.13164. Online ahead of print.

Authors

Rabeea Maqsood^{1

2}, Susie Schofield², Alexander N Bennett^{2

3}, Ahmed Khattab¹, Anthony M J Bull⁴, Nicola T Fear⁵, Christopher J Boos^{1

6}; ADVANCE Study

Affiliations

¹ Department of Medical Sciences and Public Health, Faculty of Health & Social Sciences, Bournemouth University, Bournemouth, UK.
² National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, UK.
³ Academic Department of Military Rehabilitation, Defence Medical Rehabilitation Centre, Stanford Hall Estate, Loughborough, UK.
⁴ Centre for Blast Injury Studies, Department of Bioengineering, Imperial College London, London, UK.
⁵ The Academic Department of Military Mental Health, King's College London, London, UK.
⁶ Department of Cardiology, University Hospitals Dorset, Poole Hospital, Poole, UK.

PMID: 38634349
DOI: 10.1002/pmrj.13164

Abstract

Background: Respiration is a crucial determinant of autonomic balance and heart rate variability (HRV). The comparative effect of spontaneous versus paced breathing on HRV has been almost exclusively explored in healthy adults and never been investigated in an injured military cohort.

Objective: To examine the effect of spontaneous versus paced breathing on HRV in veterans with combat-related traumatic injury (CRTI).

Design: Observational cohort study.

Setting: ArmeD serVices trAuma rehabilitatioN outComE (ADVANCE) study, Stanford Hall, UK.

Participants: The sample consisted of 100 randomly selected participants who sustained CRTI (eg, amputation) during their deployment (Afghanistan 2003-2014) and were recruited into the ongoing ADVANCE prospective cohort study.

Intervention: Not applicable.

Main outcome measure: HRV was recorded using a single-lead ECG. HRV data were acquired during a sequential protocol of 5-minute spontaneous breathing followed immediately by 5 minutes of paced breathing (six cycles/minute) among fully rested and supine participants. HRV was reported using time domain (root mean square of successive differences), frequency domain (low frequency and high frequency) and nonlinear (sample entropy) measures. The agreement between HRV during spontaneous versus paced breathing was examined using the Bland-Altman analysis.

Results: The mean age of participants was 36.5 ± 4.6 years. Resting respiratory rate was significantly higher with spontaneous versus paced breathing (13.4 ± 3.4 vs. 7.6 ± 2.0 breaths/minute; p < .001), respectively. Resting mean heart rate and root mean square of successive differences were significantly higher with paced breathing than spontaneous breathing (p < .001). Paced breathing significantly increased median low frequency power than spontaneous breathing (p < .001). No significant difference was found in the absolute power of high frequency between the two breathing protocols. The Bland-Altman analysis revealed poor agreement between HRV values during spontaneous and paced breathing conditions with wide limits of agreement.

Conclusion: Slow-paced breathing leads to higher HRV than spontaneous breathing and could overestimate resting "natural-state" HRV.

Abstract

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