COPD Patients Have a Restricted Breathing Pattern That Persists with Increased Metabolic Demands

Jennifer M. Yentes, Farahnaz Fallahtafti, William Denton, Stephen I. Rennard

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


A healthy respiratory system has variability from breath-to-breath and patients with COPD (PwCOPD) have abnormal variability in breath cycles. The aim of this study was to determine if interbreath-interval and tidal-volume variability, and airflow regularity change as metabolic demands increase (seated, standing, and walking) in PwCOPD as compared to controls. Sixteen PwCOPD (64.3 ± 7.9 yr, 61.3 ± 44.1% FEV1%predicted) and 21 controls (60.2 ± 6.8 yr, 97.5 ± 16.8% FEV1%predicted) sat, stood, and walked at their preferred-pace for five-minutes each while breathing patterns were recorded. The mean, standard deviation, and coefficient of variation of interbreath-intervals and tidal-volume, and the regularity (sample entropy) of airflow were quantified. Results were subjected to ANOVA analysis. Interbreath-interval means were shorter in PwCOPD compared to controls (p = 0.04) and as metabolic demand increased (p < 0.0001), standard deviation was decreased in PwCOPD compared to controls during each condition (p’s < 0.002). Mean tidal-volume did decrease as metabolic demand increased across groups (p < 0.0001). Coefficient of variation findings (p = 0.002) indicated PwCOPD decline in tidal-volume variability from sitting to standing to walking; whereas, controls do not. There was an interaction for airflow (p = 0.02) indicating that although, PwCOPD had a more regular airflow across all conditions, control’s airflow became more irregular as metabolic demand increased. PwCOPD’s airflow was always more regular compared to controls (p = 0.006); although, airflow became more irregular as metabolic demand increased (p < 0.0001). Healthy respiratory systems have variability and irregularity from breath-to-breath decreases with adaptation to demand. PwCOPD have more regular and restricted breathing pattern that may affect their ability to adjust in demanding situations.

Original languageEnglish (US)
Pages (from-to)245-252
Number of pages8
JournalCOPD: Journal of Chronic Obstructive Pulmonary Disease
Issue number3
StatePublished - May 3 2020


  • Entropy
  • VO
  • regularity
  • variability

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine


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