Counting the Costs of Diving (CoCoD): Evaluating the balance between performance and the physiological costs in diving.
Abstract
AbstractBreath-hold diving, even at shallow depths, comprises an assault on the regular homeostatic conditions of the body. This can lead to complications such as oxidative stress, inflammation, cerebral decompression sickness, vascular dysfunction, mental anguish, and death. As such, we aim to use freedivers as a model system to parameterise a range of physiological aberrations as measured by non-invasive biomedical optical technologies, then employ these technologies and physiological understanding to monitor cerebral responses and cognitive performance in SCUBA divers performing exercise at depth. We will use a combination of real-time and archivalnear-infrared spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS) and blood markers of tissue and organ damage to elucidate responses to hypoxemia, hyperoxia, hypercarbia, oxygen toxicity events and ischemia/reperfusion events. We will compare optical data with markers of tissue/organ damage in elite diving humans and SCUBA divers to:1.Measure cerebral homeostasis using broadband NIRS and diffuse correlation spectroscopy to investigate variation in oxygenation, cerebral blood volume, intracranial pressure, metabolic rate and cerebral water content as part of neuro-specific responses to the dive response in humans.2.Measure variation in circulating blood markers of mild traumatic brain injury to assess the potential consequences of elevated CBV and intracranial pressure on the permeability and/or integrity of the blood-brain-barrier and other neurological damage following breath-holds in humans. 3.Measure cerebral and muscle oxygenation and relative blood volume changes, heart rate and SpO2, to investigate peripheral and cerebralphysiological changes as part of the accentuated dive response experienced by humans.4.Measure variation in circulating blood markers of oxidative stress and pro-inflammatory responses including cytokine profiling, to assess the potential consequences of ischemia-reperfusion events associated with peripheral blood redistribution during breath-holds in humans. 5.Use these comparative data (a-d) to assess the extent to which changes in cerebral and whole-body homeostasis contribute towards protective mechanisms to balance the potentially negative physiological costs of an extreme dive response in elite free divers. 6.Apply the knowledge from a-e to monitor and parameterise cerebral and systemic cardiovascular aberration and potential cerebral trauma costs and implication on cognitive performance and blood gas changes in SCUBA divers, performing exercise underwater (15m & 42m); a condition that will induce hypercarbia with possible cognitive decline and oxygen toxicity This project aims to improve mission readiness and war fighter resilienceto complement the existing SBIR programme (Neurocognitive Performance Monitor in Navy Divers at Depth) developing underwater fNIRS systems by specifically developing the capacity for in-situ measurement and identificationof a broad suite of critical physiologicalparameters (heart rate, SpO2, arterial blood pressure changes, cerebral blood flow changes, cerebral blood volume changes, cerebralblood oxygen saturation, intracranial pressure, cerebral water content changes, and cerebral metabolic rate changes. This project also aims to parameterise the consequences of routine breath-holds and SCUBA dives involving exercise on circulating blood markers ofcerebral and systemic tissue trauma, as well as cognitive performance. This will assist in prescribe safer, real-time physiological boundaries, cognitive performance protocols, for military divers during training or in combat.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jun 09, 2021
- Source ID
- N000142112303
Entities
People
- Joseph Mcknight
Organizations
- Office of Naval Research
- United States Navy
- University of St Andrews