Effect of heliox on heart rate kinetics and dynamic hyperinflation during high-intensity exercise in COPD

Pierantonio Laveneziana, Gabriele Valli, Paolo Onorati, Patrizia Paoletti, Alessandro Maria Ferrazza, Paolo Palange

Research output: Contribution to journalArticlepeer-review


Respiratory mechanical abnormalities in patients with chronic obstructive pulmonary disease (COPD) may impair cardiodynamic responses and slow down heart rate (HR) kinetics compared with normal resulting in reduced convective oxygen delivery during exercise. We reasoned that heliox breathing (79% helium-21% oxygen) and the attendant reduction of operating lung volumes should accelerate HR kinetics in the transition from rest to high-intensity exercise. Eleven male ambulatory patients with clinically stable COPD undertook constant work-rate cycle testing at 80% of each individuals' maximum work capacity while breathing room air (RA) or heliox (HX), randomly. Mean response time (MRT) for HR and dynamic end-expiratory lung volume (EELV) were measured. Resting EELV was not affected by HX breathing, while exercise EELV decreased significantly by 0.23 L at isotime during HX breathing compared with RA. During HX breathing, MRT for HR significantly accelerated (p = 0.002) by an average of 20 s (i.e., 17%). Speeded MRT for HR correlated with indices of reduced lung hyperinflation, such as EELV at isotime (r = 0.88, p = 0.03), and with improved exercise endurance time (r = -0.64, p = 0.03). The results confirm that HX-induced reduction of dynamic lung hyperinflation is associated with consistent improvement in indices of cardio-circulatory function such as HR kinetics in the rest-to-exercise transition in COPD patients.

Original languageEnglish
Pages (from-to)225-234
Number of pages10
JournalEuropean Journal of Applied Physiology
Issue number2
Publication statusPublished - Feb 2011


  • Chronic obstructive pulmonary disease
  • Dynamic lung hyperinflation
  • Dyspnoea
  • Exercise
  • Heart rate kinetics
  • Heliox

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health
  • Orthopedics and Sports Medicine
  • Physiology (medical)


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