Autonomic cardiovascular adaptations to acute head-out water immersion, head-down tilt and supine position

Chouchou, Florian; Pichot, Vincent; Costes, Frédéric; Guillot, M; Barthélemy, Jean; Bertoletti, Laurent; Roche, Frédéric

doi:10.1007/s00421-019-04278-4

Cited by 19 publications

(21 citation statements)

References 52 publications

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“…Consistent with our previously published article (Chouchou et al, 2020) The thicker the arrow line, the more important the causality link. The statistical significance between the two causal directions for a given condition is marked with asterisks.…”

Section: Resultssupporting

confidence: 92%

“…Previous studies have shown an increase in parasympathetic activity and baroreflex sensitivity underpinning cardiovascular adaptations to acute HDT and WI (Chouchou et al., 2020; Fu et al., 2000; Iida et al., 1999; Miwa et al., 1996; Mourot et al., 2008; Pump et al., 1999). These adaptations were found to be similar during these two experimental conditions, except for Shiraishi et al.…”

Section: Discussionmentioning

confidence: 99%

“…The original study included 10 healthy male subjects, free of medication and cardiothoracic abnormality (Chouchou et al., 2020), but for the present analyses two subjects were excluded owing to poor ECG quality that did not enable the RE signal to be rebuilt using an ECG‐derived respiration method. Finally, eight healthy men (mean ± SD: age, 26.2 ± 5.1 years; height, 180.2 ± 7.1 cm; and weight, 75.9 ± 7.9 kg) were included in the present study.…”

Section: Methodsmentioning

confidence: 99%

“…The protocol has been described in detail in a previously published article, to which readers can refer (Chouchou et al., 2020).…”

Section: Methodsmentioning

confidence: 99%

“…In these simulations, the vascular changes involve several autonomic adaptations that can be evaluated by heart rate variability (HRV) (Anon, 1996) and baroreflex sensitivity (Hughson, Quintin, Annat, Yamamoto, & Gharib, 1993) analyses. Using such methods, previous studies have shown an increase in parasympathetic activity (Chouchou et al., 2009; Miwa, Sugiyama, Mano, Iwase, & Matsukawa, 1996; Mourot et al., 2008) and in stimulation of the cardiac baroreceptors during both HDT and WI (Chouchou et al., 2020; Fu, Sugiyama, Kamiya, & Mano, 2000; Iida et al., 1999; Pump, Videbaek, Gabrielsen, & Norsk, 1999; Shiraishi et al., 2002), whereas another study suggested a higher baroreflex sensitivity and parasympathetic activation during HDT compared with WI (Shiraishi et al., 2002). However, the physiological adaptations to WI and HDT cannot be described entirely with HRV and baroreflex sensitivity indices.…”

Section: Introductionmentioning

confidence: 99%

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Causal analyses to study autonomic regulation during acute head‐out water immersion, head‐down tilt and supine position

Corbier

Chouchou²,

Roche

et al. 2020

Experimental Physiology

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Thermoneutral head-out water immersion (WI) and 6 deg head-down tilt (HDT) are used to simulate SCUBA diving, swimming and microgravity, because these models induce an increase in central blood volume. Standard methods to analyse autonomic regulation have demonstrated an increase in parasympathetic activity and baroreflex sensitivity during these experimental conditions. However, such methods are not adapted to quantify all closed-loop interactions involved in respiratory and cardiovascular regulation. To overcome this limitation, we used Granger causality analysis between R-R intervals (RR), systolic blood pressure (SBP) and respiration (RE) in eight young, healthy subjects, recorded during 30 min periods in the supine position, WI and HDT. For all experimental conditions, we found a bidirectional causal relationship between RE and RR and between RR and SBP, with a dominant direction from RR to SBP, and a unidirectional causality from RE to SBP. These causal relationships remained unchanged for the three experimental tests. Interestingly, there was a lower causal relationship from RR to RE during WI compared with HDT. This causal link from RR to RE could be modulated by peripheral resistances. These results highlight differences in cardiovascular regulation during WI and HDT and confirm that Granger causality might reveal physiological mechanisms not accessible with standard methods.

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Section: Resultssupporting

confidence: 92%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

“…The protocol has been described in detail in a previously published article, to which readers can refer (Chouchou et al., 2020).…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Causal analyses to study autonomic regulation during acute head‐out water immersion, head‐down tilt and supine position

Corbier

Chouchou²,

Roche

et al. 2020

Experimental Physiology

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Biomedical Monitoring in Underwater Environments

Cibis

Gradl

McEwan

2022

Engineering and Medicine in Extreme Environments

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A century of exercise physiology: key concepts on coupling respiratory oxygen flow to muscle energy demand during exercise

et al. 2022

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After a short historical account, and a discussion of Hill and Meyerhof’s theory of the energetics of muscular exercise, we analyse steady-state rest and exercise as the condition wherein coupling of respiration to metabolism is most perfect. The quantitative relationships show that the homeostatic equilibrium, centred around arterial pH of 7.4 and arterial carbon dioxide partial pressure of 40 mmHg, is attained when the ratio of alveolar ventilation to carbon dioxide flow ($${\dot{V}}_{A}/{\dot{V}}_{R}{CO}_{2}$$ V ˙ A / V ˙ R CO 2 ) is − 21.6. Several combinations, exploited during exercise, of pertinent respiratory variables are compatible with this equilibrium, allowing adjustment of oxygen flow to oxygen demand without its alteration. During exercise transients, the balance is broken, but the coupling of respiration to metabolism is preserved when, as during moderate exercise, the respiratory system responds faster than the metabolic pathways. At higher exercise intensities, early blood lactate accumulation suggests that the coupling of respiration to metabolism is transiently broken, to be re-established when, at steady state, blood lactate stabilizes at higher levels than resting. In the severe exercise domain, coupling cannot be re-established, so that anaerobic lactic metabolism also contributes to sustain energy demand, lactate concentration goes up and arterial pH falls continuously. The $${\dot{V}}_{A}/{\dot{V}}_{R}{CO}_{2}$$ V ˙ A / V ˙ R CO 2 decreases below − 21.6, because of ensuing hyperventilation, while lactate keeps being accumulated, so that exercise is rapidly interrupted. The most extreme rupture of the homeostatic equilibrium occurs during breath-holding, because oxygen flow from ambient air to mitochondria is interrupted. No coupling at all is possible between respiration and metabolism in this case.

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Autonomic cardiovascular adaptations to acute head-out water immersion, head-down tilt and supine position

Cited by 19 publications

References 52 publications

Causal analyses to study autonomic regulation during acute head‐out water immersion, head‐down tilt and supine position

Causal analyses to study autonomic regulation during acute head‐out water immersion, head‐down tilt and supine position

Biomedical Monitoring in Underwater Environments

A century of exercise physiology: key concepts on coupling respiratory oxygen flow to muscle energy demand during exercise

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