DIFFERENT APPROACHES TO IDENTIFYING DYSFUNCTIONAL BREATHING (DB) IN ATHLETES

Perceived exertional dyspnoea is reported to be the most common symptom among physically active individuals of all abilities and ages and/or performance in high level athletes, potentially impacting on performance and limiting enjoyment of sporting activities. Identifying the causes of the perceived symptoms requires careful assessment with a wide range of factors potentially contributing to the reported respiratory issues. The purpose of this thesis was to investigate different assessment approaches in the identification of breathing dysfunction in exercising adults. Elite swimming and boxing require athletes to achieve relatively high minute ventilation. In Chapter 4 (Study 1 of this thesis), thirty-eight elite boxers and 44 elite swimmers completed a thorough respiratory assessment that revealed a nine-fold greater prevalence of exercise-induced bronchoconstriction in swimmers when compared with boxers. These results suggested that the combination of a sustained high ventilation and provocative training environment may impact the susceptibility of athletes to this condition. Dysfunctional breathing may mimic and/or co-exist with exercise-induced bronchoconstriction. The use of specific questionnaires may improve the identification of this condition in athletes. In Chapter 5 (Study 2 of this thesis), 9% of the 428 healthy, physically active young adults who completed the Nijmegen Questionnaire had a score ? 23, suggestive of a dysfunctional breathing status. A separate cohort of 104 athletes underwent an indirect bronchoprovocation challenge and completed the Nijmegen questionnaire. The sensitivity, specificity, positive and negative predicted values suggested that the Nijmegen score was a poor predictor of a positive bronchoprovocation challenge in athletes and therefore is not suitable to detect dysfunctional breathing in athletes. The posture an athlete holds during exercise may alter breathing pattern and increase reported exercise induced respiratory symptoms. In order to investigate whether respiratory parameters are affected by different postural positions, in Chapter 6 (Study 3 of this thesis), 15 healthy male athletes performed a 10-minute, high intensity cycling test with normal shoulder position and with hunched shoulders. Results of this study showed that cycling with hunched shoulders at high intensities over a prolonged period leads to an increase in perceived dyspnoea and suggested that posture may contribute to reports of respiratory symptoms during exercise in the absence of cardio-pulmonary disease. With the aim of investigating the effect of different postural positions on the ventilatory excursion, in Chapter 7 (Study 4 of this thesis), 15 healthy male athletes performed baseline spirometric measurements and 10-minutes cycling challenges with normal shoulder position and with hunched shoulders, while undergoing simultaneous data collection with optoelectronic plethysmography. The findings of this study suggested that respiratory excursion and lung volume compartmentalisation at both rest and during high intensity exercise are affected by the position of the shoulders. In conclusion, athletes who train and compete in provocative environments at a sustained high ventilation have an increased susceptibility to airway dysfunction. No existing questionnaire is sensitive enough to identify dysfunctional breathing and differentiate it from other respiratory conditions, such as exercise-induced bronchoconstriction. Exercising for a prolonged period at high intensities with hunched shoulders triggers increased abdominal contribution to vital capacity and a subsequent increase in perception of breathing sensation without a significant effect on physiological markers of respiratory function. Further investigations should be undertaken in order to develop a new questionnaire that is more suitable for an athletic population and has higher accuracy in identifying symptoms associated with exercise induced breathing impairment. Precise detection of distortions between compartmental contributions in exercising individuals may play an important role in the differential diagnosis of dysfunctional breathing.