Eva-Maria S Bønnelycke, Tommaso A Giacon, Gerardo Bosco, Jana M Kainerstorfer, Matteo Paganini, Alexander Ruesch, Jingyi Wu, J Chris McKnight
{"title":"训练有素的自由潜水员在雪橇辅助下潜至两种不同深度时的脑血流动力学和全身生理变化。","authors":"Eva-Maria S Bønnelycke, Tommaso A Giacon, Gerardo Bosco, Jana M Kainerstorfer, Matteo Paganini, Alexander Ruesch, Jingyi Wu, J Chris McKnight","doi":"10.1152/ajpregu.00085.2024","DOIUrl":null,"url":null,"abstract":"<p><p>Although existing literature covers significant detail on the physiology of human freediving, the lack of standardized protocols has hindered comparisons due to confounding variables such as exercise and depth. By accounting for these variables, direct depth-dependent impacts on cardiovascular and blood oxygen regulation can be investigated. In this study, depth-dependent effects on <i>1</i>) cerebral hemodynamic and oxygenation changes, <i>2</i>) arterial oxygen saturation ([Formula: see text]), and <i>3</i>) heart rate during breath-hold diving without confounding effects of exercise were investigated. Six freedivers (51.0 ± 12.6 yr; means ± SD), instrumented with continuous-wave near-infrared spectroscopy for monitoring cerebral hemodynamic and oxygenation measurements, heart rate, and [Formula: see text], performed sled-assisted breath-hold dives to 15 m and 42 m. Arterial blood gas tensions were validated through cross-sectional periodic blood sampling. Cerebral hemodynamic changes were characteristic of breath-hold diving, with changes during ascent from both depths likely driven by decreasing [Formula: see text] due to lung expansion. Although [Formula: see text] was significantly lower following 42-m dives [<i>t</i>(5) = -4.183, <i>P</i> < 0.05], mean cerebral arterial-venous blood oxygen saturation remained at 74% following dives to both depths. Cerebral oxygenation during ascent from 42 m may have been maintained through increased arterial delivery. Heart rate was variable with no significant difference in minimum heart rate between both depths [<i>t</i>(5) = -1.017, <i>P</i> > 0.05]. This study presents a standardized methodology, which could provide a basis for future research on human freediving physiology and uncover ways in which freedivers can reduce potential risks of the sport.<b>NEW & NOTEWORTHY</b> We present a standardized methodology in which trained breath-hold divers instrumented with wearable near-infrared spectroscopy (NIRS) technology and a cannula for arterial blood sampling completed sled-assisted dives to two different dive depths to account for the confounding factors of exercise and depth during breath-hold diving. In our investigation, we highlight the utility of wearable NIRS systems for continuous hemodynamic and oxygenation monitoring to investigate the impacts of hydrostatic pressure on cardiovascular and blood oxygen regulation.</p>","PeriodicalId":7630,"journal":{"name":"American journal of physiology. Regulatory, integrative and comparative physiology","volume":" ","pages":"R553-R567"},"PeriodicalIF":2.2000,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Cerebral hemodynamic and systemic physiological changes in trained freedivers completing sled-assisted dives to two different depths.\",\"authors\":\"Eva-Maria S Bønnelycke, Tommaso A Giacon, Gerardo Bosco, Jana M Kainerstorfer, Matteo Paganini, Alexander Ruesch, Jingyi Wu, J Chris McKnight\",\"doi\":\"10.1152/ajpregu.00085.2024\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><p>Although existing literature covers significant detail on the physiology of human freediving, the lack of standardized protocols has hindered comparisons due to confounding variables such as exercise and depth. By accounting for these variables, direct depth-dependent impacts on cardiovascular and blood oxygen regulation can be investigated. In this study, depth-dependent effects on <i>1</i>) cerebral hemodynamic and oxygenation changes, <i>2</i>) arterial oxygen saturation ([Formula: see text]), and <i>3</i>) heart rate during breath-hold diving without confounding effects of exercise were investigated. Six freedivers (51.0 ± 12.6 yr; means ± SD), instrumented with continuous-wave near-infrared spectroscopy for monitoring cerebral hemodynamic and oxygenation measurements, heart rate, and [Formula: see text], performed sled-assisted breath-hold dives to 15 m and 42 m. Arterial blood gas tensions were validated through cross-sectional periodic blood sampling. Cerebral hemodynamic changes were characteristic of breath-hold diving, with changes during ascent from both depths likely driven by decreasing [Formula: see text] due to lung expansion. Although [Formula: see text] was significantly lower following 42-m dives [<i>t</i>(5) = -4.183, <i>P</i> < 0.05], mean cerebral arterial-venous blood oxygen saturation remained at 74% following dives to both depths. Cerebral oxygenation during ascent from 42 m may have been maintained through increased arterial delivery. Heart rate was variable with no significant difference in minimum heart rate between both depths [<i>t</i>(5) = -1.017, <i>P</i> > 0.05]. This study presents a standardized methodology, which could provide a basis for future research on human freediving physiology and uncover ways in which freedivers can reduce potential risks of the sport.<b>NEW & NOTEWORTHY</b> We present a standardized methodology in which trained breath-hold divers instrumented with wearable near-infrared spectroscopy (NIRS) technology and a cannula for arterial blood sampling completed sled-assisted dives to two different dive depths to account for the confounding factors of exercise and depth during breath-hold diving. In our investigation, we highlight the utility of wearable NIRS systems for continuous hemodynamic and oxygenation monitoring to investigate the impacts of hydrostatic pressure on cardiovascular and blood oxygen regulation.</p>\",\"PeriodicalId\":7630,\"journal\":{\"name\":\"American journal of physiology. 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Cerebral hemodynamic and systemic physiological changes in trained freedivers completing sled-assisted dives to two different depths.
Although existing literature covers significant detail on the physiology of human freediving, the lack of standardized protocols has hindered comparisons due to confounding variables such as exercise and depth. By accounting for these variables, direct depth-dependent impacts on cardiovascular and blood oxygen regulation can be investigated. In this study, depth-dependent effects on 1) cerebral hemodynamic and oxygenation changes, 2) arterial oxygen saturation ([Formula: see text]), and 3) heart rate during breath-hold diving without confounding effects of exercise were investigated. Six freedivers (51.0 ± 12.6 yr; means ± SD), instrumented with continuous-wave near-infrared spectroscopy for monitoring cerebral hemodynamic and oxygenation measurements, heart rate, and [Formula: see text], performed sled-assisted breath-hold dives to 15 m and 42 m. Arterial blood gas tensions were validated through cross-sectional periodic blood sampling. Cerebral hemodynamic changes were characteristic of breath-hold diving, with changes during ascent from both depths likely driven by decreasing [Formula: see text] due to lung expansion. Although [Formula: see text] was significantly lower following 42-m dives [t(5) = -4.183, P < 0.05], mean cerebral arterial-venous blood oxygen saturation remained at 74% following dives to both depths. Cerebral oxygenation during ascent from 42 m may have been maintained through increased arterial delivery. Heart rate was variable with no significant difference in minimum heart rate between both depths [t(5) = -1.017, P > 0.05]. This study presents a standardized methodology, which could provide a basis for future research on human freediving physiology and uncover ways in which freedivers can reduce potential risks of the sport.NEW & NOTEWORTHY We present a standardized methodology in which trained breath-hold divers instrumented with wearable near-infrared spectroscopy (NIRS) technology and a cannula for arterial blood sampling completed sled-assisted dives to two different dive depths to account for the confounding factors of exercise and depth during breath-hold diving. In our investigation, we highlight the utility of wearable NIRS systems for continuous hemodynamic and oxygenation monitoring to investigate the impacts of hydrostatic pressure on cardiovascular and blood oxygen regulation.
期刊介绍:
The American Journal of Physiology-Regulatory, Integrative and Comparative Physiology publishes original investigations that illuminate normal or abnormal regulation and integration of physiological mechanisms at all levels of biological organization, ranging from molecules to humans, including clinical investigations. Major areas of emphasis include regulation in genetically modified animals; model organisms; development and tissue plasticity; neurohumoral control of circulation and hypertension; local control of circulation; cardiac and renal integration; thirst and volume, electrolyte homeostasis; glucose homeostasis and energy balance; appetite and obesity; inflammation and cytokines; integrative physiology of pregnancy-parturition-lactation; and thermoregulation and adaptations to exercise and environmental stress.