Proceedings of The Physiological Society
King's College London (2009) Proc Physiol Soc 14, PC38
Effect of 5-weeks high-frequency airway occlusion training on respiratory function and breathlessness
T. A. Morris1, D. P. Sumners2, D. A. Green1
1. Division of Applied Biomedical Research, King's College London, London, United Kingdom. 2. Sport and Exercise Research Centre, London South Bank University, London, United Kingdom.
High frequency airway occlusion (HFAO) increases maximal inspiratory mouth pressure generation (Sumners et al., 2008) but as yet the chronic training effects have not been investigated. Therefore the aim of this study was to investigate the effects of 5 weeks training with high frequency airway occlusion on lung function, respiratory function, autonomic function and sensation in healthy subjects. The study had local ethical approval and informed consent was obtained. The protocol consisted of a pre-training testing session, followed by five weeks training (60 breaths/day, 5 days/week) with a HFAO device (youbreathe®), followed by an identical post-testing session. Pre and post-testing sessions consisted of breath-by-breath analysis during 3 conditions: 3 minutes tidal breathing, 1 minute inspiratory resistive-loaded breathing (19 cmH2O.l-1.s-1) and 1 minute maximum voluntary hyperventilation. In addition a battery of lung function tests, maximal dynamic and static mouth pressures, maximal dynamic inspiratory flow and maximal dynamic inspiratory volumes were determined (mean±SEM). Dypnoea was rated during HFAO and resistive-loaded breathing on a BORG scale (0-10). Physiological parameters were tested PRE vs. POST with Student's paired t-test and dyspnoea with a Wilcoxon Signed Rank test with significance assumed at p<0.05. Following 5 weeks HFAO training significant improvement in maximal dynamic mouth pressures (-6.27±0.42 to -8.58±0.63 mmHg; p<0.05) and maximal static mouth pressures (-71±3.01 to -79.44±3.78 mmHg; p<0.05) were observed. In addition, mouth pressure (-4.16±0.32 to -4.76±0.35 L/sec; p<0.05) was increased during maximal voluntary hyperventilation. Furthermore HFAO training resulted in significant reductions in dyspnoea both during HFAO (2.74±0.28 to 2.21±0.27; p<0.05) and inspiratory resistance (4.42±0.34 to 3.21±0.21; p<0.05). Therefore, 5 weeks of HFAO training evokes significant improvements both in dynamic and static maximal respiratory mouth pressure generation, and a reduction in dyspnoea during loaded breathing in young healthy individuals. Such findings suggest that transient inspiratory vibratory stimulus may provide a useful training stimulus for individuals whom experience respiratory-related limitations.
Where applicable, experiments conform with Society ethical requirements