Diving physiology in dolphins and humans

During diving, the body is exposed to a number of environmental stressors that result in physiological responses. Many of these responses are common across both humans and dolphins. One of the best known is the dive response, historically referred to as the “master switch of life,” a defense against asphyxia. This is enacted during submersion and consists of a reduction in heart rate and a redistribution of blood to high-priority organs. Increasing hydrostatic pressure during descent compresses all air-filled spaces, resulting in structural changes, and alters blood gas tensions and hemodynamics. In this chapter, we will briefly outline a number of physiological changes associated with diving and compare and contrast these responses between humans and dolphins.