The influence of inspiratory muscle training upon exertional breathlessness in healthy elderly men and women

Breathlessness is a common complaint amongst seemingly, healthy, elderly people, mild exertion being sufficient to illicit extremely debilitating sensations. This places an unacceptable physical limitation on the individual and reduces their quality of life. Previous investigators have suggested that the strength and condition of the respiratory muscles are contributing factors in the sensation of breathlessness on exertion (Aldrich, 1990; Killian, 1990). Therefore, the aim of the research contained within the thesis, was firstly; to characterise the respiratory muscle function of a group of healthy elderly subjects, and secondly; to assess the influence of inspiratory muscle training upon the genesis of exertional breathlessness in healthy, elderly men and women. The respiratory muscle strength of a group of healthy, elderly people was determined by measuring the maximum static and dynamic respiratory pressures on two occasions separated by approximately one week. The results suggested the maximum (or minimum) mouth pressure averaged over a one second period, measured using a hand-held mouth pressure meter (Precision Medical Ltd, U.K.), represents a reliable and reproducible index of respiratory muscle function in healthy, elderly subjects. In addition, the data was used to establish a contemporary set of prediction equations, and normal values were derived to facilitate the estimation of respiratory muscle strength in healthy, elderly subjects. Finally, the data suggested that the respiratory muscle function of healthy, elderly people declines with advancing age. However, the strength of the respiratory muscles does not correlate significantly with indices of body size, but is strongly influenced by customary levels of physical activity. Breathlessness during both cycle ergometry and treadmill walking was measured using both the visual analogue scale and the modified Borg scale. For healthy, elderly subjects, poor correlations existed between exertional breathlessness and the prevailing level of ventilation. Mean breathlessness scores were therefore used as an alternative index of breathlessness. The use of this parameter was validated by examining its reproducibility during both cycle and treadmill exercise. During cycle ergometry, the modified Borg scale provided more reproducible ratings of breathlessness than the visual analogue scale. However, a treadmill walking protocol was developed, which induces breathlessnesss afely, and during which, elderly people rated their breathlessnessr eproducibly using both the VAS and modified Borg scale. In general, elderly subjects preferred using the modified Borg scale. Finally, the role of the respiratory muscles in the genesis of exertional breathlessness was examined by determining the influence of inspiratory muscle training upon the sensation of breathlessness during treadmill exercise. Respiratory muscle training, using an inspiratory muscle training device, increased the inspiratory muscle strength of healthy, elderly men and women by approximately 20% and ameliorated the sensation of exertional breathlessness by 21.4%. Inspiratory muscle training was also associated with improvements in elderly people's subjective perception of their breathing, their ability to perform daily routine activities and their "well-being". Together, these results suggest that inspiratory muscle training may improve the quality of life of healthy, elderly people.