Ultrasound Imaging of the Diaphragm During Yoga Breathing

INTRODUCTION The practice of yoga in recent years is becoming more common. Originating in India, yoga combines physical postures with a philosophy of life and breathing (pranayama). One of the breaths used during yoga practice is the so-called ujjayi or victorious breath. It consists of the voluntary contraction of the muscles of the larynx both in inspiration and expiration. This reduces the diameter of the larynx, reducing airflow and thus increasing intrathoracic pressure, as well as increasing expiratory/inspiratory time and reducing respiratory rate and dead space. It also increases oxygen saturation in healthy subjects, increasing respiratory effort. Several studies have verified the relationship between ujjayi breathing and increased BRS (cardiovagal baroreflex sensitivity), by stimulation of the parasympathetic system at the glottis level. This would favor a decrease in heart rate, as well as better control of stress and anxiety. The cardiovascular and respiratory effects studied with ujjayi breathing have not evaluated the effect that this breath has on the activation of the respiratory muscles, mainly the diaphragm. The diaphragm is the main inspiratory muscle and as such, lung volumes and intrathoracic pressures created during respiration depend on its activation and position. In recent years, ultrasound has become a technique widely used by pulmonologists and intensivists. It is an easy technique to perform, reproducible, non-ionizing, allows bilateral comparison, non-invasive and non-painful and whose results can broaden the information from other techniques such as spirometry and radiography. There are standardized protocols to measure the diaphragmatic excursion, the thickness of the diaphragm HYPOTHESIS: ujjayi breathing is capable of generating greater activation of the diaphragm in subjects healthy with respect to spontaneous or pursed-lip breathing. OBJECTIF: study and compare the activation and work of the diaphragm in different type of brea