ABSTRACT
This chapter focuses on the consequences of diving on the thorax including the changes in hemodynamics and pulmonary mechanics, and the increased respiratory heat loss, both factors playing key roles in the limitation of cardiopulmonary function at depth. To breathe during diving there must be a measure of agreement between the pressure of the breathing source and the hydrostatic pressure on the diver’s chest. Due to the constant value of the pressure by volume product, measured at constant temperature in perfect gases, the density of a gas mixture increases linearly with the absolute pressure, expressed in atmospheres absolute. Breathing high density gas mixtures constitutes a condition of resistive internal ventilatory loading. The changes in heart rate and systemic blood pressure were often studied at depth. Under hyperbaric environment, several studies have reported bradycardia in man and animals and also in isolated heart exposed to high pressure.
