François Galland's research while affiliated with Institut de France and other places

Publications (13)

Article
Full-text available
Introduction : l'analyse spectrale de la variabilité de l'intervalle RR permet une évaluation de l'activité du système nerveux autonome (SNA). Le but de cette étude était de déterminer les effets d'un programme militaire de formation à la plongée sous marine sur l'activité du SNA. Méthodes : Une mesure de la pression artérielle ainsi qu'un enregist...
Article
The present study was designed to assess the cardiac changes induced by cold water immersion compared with dry conditions during a prolonged hyperbaric and hyperoxic exposure (ambient pressure between 1.6 and 3 ATA and PiO(2) between 1.2 and 2.8 ATA). Ten healthy volunteers were studied during a 6 h compression in a hyperbaric chamber with immersio...
Article
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To evaluate the effects of a submaximal exercise performed 2 h before a simulated dive on bubble formation and to observe the haemodynamic changes and their influence on bubble formation. 16 trained divers were compressed in a hyperbaric chamber to 400 kPa for 30 min and decompressed at a rate of 100 kPa/min with a 9 min stop at 130 kPa (French Nav...
Article
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Oxygen divers undergo environmental stressors such as immersion, ventilation with scuba, cold exposure, and increased ambient pressure. All of these stressors may be responsible for acute hemodynamic modifications. We hypothesized that repeated hyperbaric hyperoxia exposure induces long-term cardiovascular modifications. A Doppler echocardiography...
Article
The consequences of a prolonged total body immersion in cold water on the muscle function have not been documented yet, and they are the object of this French Navy research program. Ten elite divers were totally immerged and stayed immobile during 6 h in cold (18 and 10 degrees C) water. We measured the maximal voluntary leg extension (maximal volu...
Article
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A single bout of aerobic exercise 24 h before a dive significantly reduces the formation of circulating venous gas emboli (VGE) on decompression. The purpose of this investigation was to determine the effect of aerobic exercise 2 h before a dive. There were 16 trained military divers who were compressed to 30 msw (400 kPa) for 30 min breathing air...
Article
Objective. – Decompression MN 90 Table is used for air diving by military divers and both sports divers in France. In the aim to confirm MN 90 safety, we studied 61 decompression sicknesses observed in the French Navy for 1990–2002.Method. – Each year 1800 divers carry out 150 000 dives±10%. Divers are 1600 ship divers (dives less than 35 m-sub-wat...
Article
The French Navy uses the Marine Nationale 90 (MN90) decompression tables for air dives as deep as 60 msw. The resulting incidence of decompression sickness (DCS) for deep dives (45-60 msw) is one case per 3000 dives. Three protocols with experimental ascent profiles (EAPs) were tested in the wet compartment of a hyperbaric chamber. For each protoco...
Article
Full-text available
The N-terminal pro brain natriuretic peptide (N-BNP) is a promising cardiac natriuretic peptide used as a clinical hormonal marker in cardiac dysfunction. The main stimulus for N-BNP synthesis and secretion is cardiac wall stress, which is recognized as a common denominator of many cardiac diseases. Diving is associated with environmental factors l...
Article
Full-text available
In the present study, we observed the haemodynamic changes, using echocardiography and Doppler, in ten healthy volunteers during 6 h of compression in a hyperbaric chamber with a protocol designed to reproduce the conditions as near as possible to a real dive. Ambient pressure varied from 1.6 to 3 atm (1 atm=101.325 kPa) and partial pressure of ins...
Article
Full-text available
Many studies have described the physiology of water immersion (WI), whereas few have focused on post WI physiology, which faces the global water loss of the large WI diuresis. Therefore, we compared hemodynamics and vasomotor tone in 10 trained supine divers before and after two 6h sessions in dry (DY) and head out WI environments. During each expo...

Citations

... A negative inotropic effect of hyperoxia should also be considered. It has been demonstrated during exposure to normobaric hyperoxia [11,16,18,19]. However, the negative inotropic effect of oxygen generally does not persist during exposure to HH [20,21], as increased ambient pressure causes the elevation in cardiac contractility [8,22,23]. ...
... It is not true that after immersed cooling a subject is in a vasoplegic state. In fact the reduction in large cold-induced arterial and venous vasoconstrictive tone occurs over several hours (Robinet et al., 2006;Boussuges et al., 2009;Florian et al., 2013;Riera et al., 2014). Yes removing the squeezing effect of hydrostatic pressure precipitate rescue collapse (Lloyd, 1992). ...
... Age and depth were mainly described as risk factors of a DCS onset rather than prognostic factors [3,31]. For example, it has been demonstrated that the risk of spinal cord DCS was minimal when the dives were conducted within the diving depth range 0-40 m [31]. ...
... Hyperoxic exposure has a major impact on cardiovascular function in healthy subjects. Numerous studies have shown that cardiovascular responses to acute hyperoxia include a decrease in cardiac output related to the simultaneous decreases in heart rate and stroke volume [41][42][43]. Increases in mean blood pressure and systemic vascular resistance, and a decrease in arterial compliance, have been documented in resting healthy volunteers breathing pure oxygen [41,44,45]. Such an effect of oxygen appears to be related to its vasoconstrictive action on the peripheral vascular system. ...
... However, depending on when venous blood samples are taken in relation to the WI, diver aldosterone levels may not change before and after single and consecutive dives, although increases in central SNS activity were seen with the increased LF/HF ratio (85,87,177). The changes in heart rate may affect regional and systematic blood flow. ...
... Our previous study on the effect of a single session of recreational SCUBA (rSCUBA) diving on the CV system (Žarak et al., 2020) showed moderate but reversible changes in biomarkers of cardiac (N-terminal prohormone of brain natriuretic peptide (NT-proBNP) and high-sensitivity troponin I (hs-TnI)) and muscle damage (myoglobin (Mb) and galectin-3 (Gal-3)), and vascular endothelial activation (vascular endothelial growth factor (VEGF) and endothelin-1 (ET-1)). Other studies found similar results for NT-proBNP after both single rSCUBA diving sessions (Gempp et al., 2005;Grassi et al., 2009;Passino et al., 2011) and technical (dives deeper than 40 m with an obligatory decompression stop (CMAS, 2012)) diving sessions Marinovic et al., 2010). Further, Sureda et al. (2012) found similar results; a decrease in ET-1 and an increase in VEGF in a group of divers who performed a single technical SCUBA diving session. ...
... This is despite recent hyperbaric chamber studies not supporting this view. 13,14 With regard to the pathophysiological approach to decompression, what we know currently is not enough to predict which decompression procedures are better than others in terms of DCS prevention. At present, the only way to compare different decompression strategies is to test them in underwater practice, but this means monitoring a huge number of dives, which is expensive and dif cult to achieve in a reasonable amount of time, especially for technical dives. ...
... Likewise, several studies have demonstrated that physical activity or sauna exposure, some hours before the dive, could have a cardiovascular-mediated preventive effect on VGE formation [17][18][19][20]. An animal model with rats demonstrated that a single bout of exercise 20 h pre-dive reduces VGE post-dive and also DCS occurrence and related mortality [21]. ...
... O predomínio de estudos demonstrando a superioridade da CI em relação a outros métodos na recuperação muscular se deve a sua atuação de modo sistêmico com seus efeitos positivos se diferenciando conforme o órgão ou sistema sobre o qual atua e aspectos considerado, conforme descrito a seguir: 1) metabolismo tecidual: redução da demanda de energia por meio da redução estresse metabólico da fibra muscular (Hom et al., 2004;White e Wells, 2013); 2) fluxo sanguíneo: vasoconstrição reflexa (Peiffer et al., 2009) responsável pela redução da influência de componentes inflamatórios responsáveis por dano à fibra muscular e edema (Pournot et al., 2011); 3) desvio de fluxo sanguíneo e edema: em associação com o efeito descrito anteriormente, a CI demonstrou em vários estudos reduzir o fluxo sanguíneo para fibras musculares sob condição de estresse induzido pelo exercício, reduzindo o potencial existente para instalação de edema nas mesmas, esse aspecto é ainda reforçado pela pressão hidrostática exercida pela água na qual o segmento encontra-se imerso (Peiffer et al., 2009;White e Wells, 2013); 4) efeitos neuromusculares: a redução da temperatura do segmento em imersão atua também sobre o sistema nervoso, reduzindo a velocidade de condução neural (Coulange et al., 2006) e consequentemente o espasmo muscular e dor muscular tardia em resposta ao exercício (Goodall e Howatson, 2008); 5) efeitos cardiovasculares: a imersão em água gelada tanto parcial (membros inferiores) quanto total (até o pescoço) têm demonstrado alterar a atividade cardíaca, restaurar o volume sanguíneo em vasos centrais antes desviado para os segmentos sob estresse induzido pelo exercício e aumentar a pré-carga cardíaca (Peiffer et al., 2009;Herrera et al., 2010); 6) efeitos endócrinos: o exercício e o resfriamento são considerados agentes estressores para o corpo, os efeitos do repouso e da CI sobre a alteração dos hormônios circulantes e a recuperação muscular ainda são pouco estudados e seus efeitos sobre o desempenho ainda precisam ser conhecidos. Esses hormônios modulam, por exemplo, o fluxo sanguíneo, a frequência cardíaca e respiratória, podendo deste modo serem relevantes durante a recuperação pós-exercício (White e Wells, 2013). ...
... Likewise, several studies have demonstrated that physical activity or sauna exposure, some hours before the dive, could have a cardiovascular-mediated preventive effect on VGE formation [17][18][19][20]. An animal model with rats demonstrated that a single bout of exercise 20 h pre-dive reduces VGE post-dive and also DCS occurrence and related mortality [21]. ...