Acute cardiovascular responses to slow and deep breathing

Slow and deep breathing has long been regarded as a nonpharmacological method for dealing with several physiological and emotional imbalances, and widely used for relaxation purposes. There is, however, limited understanding of the putative mechanisms by which slow and deep breathing acutely impacts the cardiovascular and autonomic systems to elicit chronic adaptations.

The present thesis explored how the manipulation of breathing patterns and intrathoracic pressure during slow and deep breathing could further the understanding of the regulatory mechanisms that underpin the acute cardiovascular response to slow and deep breathing.

The aim of this project was three-fold:

1) To understand the independent effects of breathing frequency and tidal volume on the cardiovascular and autonomic response to slow and deep breathing,

2) To explore the increasingly negative intrathoracic pressure to the magnitude of cardiovascular respiratory modulation elicited by slow and deep breathing, and

3) To provide insight into the cardiac and systemic haemodynamics in response to slow and deep breathing combined with different modalities of resisted breathing.

The results of this project provide novel information regarding the mechanisms contributing to the acute cardiovascular response to slow and deep breathing. These new insights may contribute to the development of more effective slow and deep breathing interventions, geared towards maximising the perturbation to the cardiovascular control systems.