Autonomic cardiovascular adaptations to acute head-out water immersion, head-down tilt and supine position.
Eur J Appl Physiol
; 120(2): 337-347, 2020 Feb.
Article
em En
| MEDLINE
| ID: mdl-31813043
ABSTRACT
PURPOSE:
Thermoneutral head-out water immersion (WI) and 6° head-down tilt (HDT) have been considered as suitable models to increase central blood volume and simulate autonomic cardiovascular adaptations to microgravity, swimming or scuba diving. However, any differences in autonomic cardiovascular adaptations are still unclear. In this study, we hypothesized that WI induces a higher activation of arterial baroreceptors and the parasympathetic system.METHODS:
Ten healthy men underwent 30 min of WI, HDT, and a supine position (SP). RR intervals (RRI) and blood pressure (BP) were continuously monitored. High frequency power (HF), low frequency power (LF) and LF/HF ratio were calculated to study sympathetic and parasympathetic activities, and a spontaneous baroreflex method was used to study arterial baroreflex sensitivity (aBRS). Lung transfer of nitric oxide and carbon monoxide (TLNO/TLCO), vital capacity and alveolar volume (Vc/VA) were measured to study central blood redistribution.RESULTS:
We observed (1) a similar increase in RRI and decrease in BP; (2) a similar increase in HF power during all experimental conditions, whereas LF increased after; (3) a similar rise in aBRS; (4) a similar increase in Vc/VA and decrease in TLNO/TLCO in all experimental conditions.CONCLUSIONS:
These results showed a cardiac parasympathetic dominance to the same extent, underpinned by a similar arterial baroreflex activation during WI and HDT as well as control SP. Future studies may address their association with cold or hyperoxia to assess their ability to replicate autonomic cardiovascular adaptations to microgravity, swimming or scuba diving.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Sistema Nervoso Autônomo
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Pressão Sanguínea
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Água
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Decúbito Dorsal
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Decúbito Inclinado com Rebaixamento da Cabeça
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Frequência Cardíaca
Limite:
Adult
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Humans
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Male
Idioma:
En
Revista:
Eur J Appl Physiol
Assunto da revista:
FISIOLOGIA
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
França