Unsatisfied inspiration is a sensory experience where individuals feel like they are not getting enough air into their lungs. This sensation is highly prevalent in patients with chronic lung disease due to pathological mechanical constraints on lung expansion. These constraints can compromise exercise tolerance and lead to negative emotional and behavioural responses to physical activity. Traditionally, this sensation has been considered relatively absent in healthy individuals. However, recent work by Ferguson et al., (2024) (the application intern) revealed that 34% of young, healthy participants reported experiencing unsatisfied inspiration. These findings further suggested that constraints on inspiration may be the predominant physiological driver of this distressing breathing sensation in young healthy adults. Additionally, the unsatisfied inspiration group had a significantly higher selection frequency of “breathing” being their primary limitation at the end of the exercise. Although the underlying cause of this physiological constraint remains unclear it is plausible that these individuals may display an unconventional breathing pattern (i.e., rate and depth), coordination, or an inability to maintain optimal breathing techniques throughout longer bouts of exercise.
Respiratory muscle training may have the potential to alleviate this sensation of unsatisfied inspiration and improve performance. Specifically, isocapnic training allows individuals to breathe as hard and fast as they need to sufficiently train their respiratory system while maintaining constant carbon dioxide levels. This training modality may help individuals target the respiratory system by aiding in the development of breathing techniques which optimize respiratory muscle coordination and power, and subsequently reduce the distressing sensation of breathlessness. Moreover, respiratory endurance training may also contribute to the desensitization of the individual to higher exercise ventilations, which may in turn contribute to a reduced perception of breathlessness. However, previous research has largely focused on resistive breathing training devices, which resulted in contradicting findings on exercise performance. One device, the Spiro-Tiger has attempted to provide a device capable of addressing respiratory endurance rather than strength, however, the complexity and cost of this product hindered its growth in the North American market.
The Isocapnic BreathWayBetter (BWB) (Isocapnic Technologies Inc, Kelowna, Canada) is a commercially available, affordable, portable device, paired with the free user-friendly app that allows for personalized training programs with visual guidance that can be performed anywhere. However, its efficacy in improving measures of perceptual responses, such as unsatisfied inspiration following a prolonged training regimen remains relatively unknown. Therefore, the primary aim of this study is to investigate the effects of 5 weeks of respiratory endurance training with the BWB device on the multidimensional components of breathlessness (e.g., immediate perception and emotional/behavioural aspects). Additionally, we aim to elucidate the physiological measures associated with reductions in these perceptual measures, through a comprehensive assessment of respiratory mechanics and muscle activation patterns, as well as operational lung volumes.
This research being done into the effectiveness of targeted respiratory training with subjects identified with unsatisfied inspiration will have great benefit to the company as it expands its user base, and increases awareness of the effectiveness of their product and training methodologies. Olivia (intern) will gain new skills by working with an industry partner to better understand how her current research skills can inform the development of effective medical devices. Additionally, this work will complement her previous research in exercise and breathlessness, providing hands-on experience in testing the efficacy of a medical device on breathlessness and respiratory physiology. Lastly, gaining experience working in industry will be an invaluable asset as she moves forward in her research career.