About this Research Topic
The dive response is a number of physiological changes associated with diving, including bradycardia and reduced cardiac output, resulting in increased arterial blood pressure despite peripheral vasoconstriction in human divers. It was proposed that the main objective of the dive response is to conserve oxygen for hypoxia sensitive organs like the brain and the heart, but in marine adapted species like dolphins, it possibly also helps assure that the available oxygen is used in a way to extend the aerobic dive limit. In some species, and human, it appears that the spleen contracts, releasing red blood cells into the bloodstream, and thereby, increasing the available oxygen. However, the reflex mechanisms and their interdependencies (diving reflex, trigeminal cardiac reflex, baroreflex among others) are still poorly known in different species including humans.
Likewise, studies investigating human reactions to the marine environment at depth are scarce. Furthermore, apnea could very well serve as an excellent model of natural hypoxia to increase hypoxic tolerance which could be complementary or even replace the current techniques of hypoxic training and/or preconditioning at natural or simulated altitude. However, to date, there is little information available on the optimal apnea training modalities for improving performance in sportsmen and women. Finally, the consequences of the lack of oxygen on health go far beyond the physiopathology of divers. The human body's resistance to hypoxia interests several disciplinary fields and varied pathologies such as sudden infant death syndrome, sleep apnea, loss of consciousness, neurodegenerative pathologies and finally cancers.
This Research Topic focuses on the cardiovascular, respiratory, metabolic and up to molecular genetic changes of the human body to apnea and the combination of apnea with exercise and training. The different reflexes involved in coping with this hypoxic situation will be discussed. The effects of apnea training in the short and long term on the different systems will also be discussed. Better understanding of the physiopathological consequences of apnea on the lungs, the cardiovascular system and the brain in the more or less long term in healthy individuals is a focus additionally.
Possible applications in the health field of continuous and/or intermittent hypoxia may also be relevant to this topic. The animal model specifically adapted to the aquatic environment and hypoxic situations will shed light on other human pathologies where resistance to hypoxia is paramount.
Keywords: Apnea, hypoxia, training, marine mammals
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