title: Flow velocity in carotid artery in humans during immersions and underwater swimming.
abstract: Heart rate and flow velocity in the common carotid artery were examined on eight subjects in various underwater conditions. The heart rate decreased more markedly during whole-body immersion than during head-out immersion. The end-diastolic flow velocity and the flow-velocity integral in a cardiac cycle during whole-body immersion increased more markedly than during head-out immersion. Differences in heart rate and flow velocity were not detected between sitting and prone positions in whole-body immersion. Heart rate increased at the beginning and after underwater swimming. The peak systolic flow velocity increased significantly after the end of underwater swimming. The flow-velocity integral in a cardiac cycle decreased during underwater swimming, but in a minute did not change significantly. These results suggest that facial immersion is important in eliciting pronounced carotid artery flow-velocity response in addition to the heart-rate response and that underwater exercise influences these responses. However, underwater posture apparently does not influence them.
authors.affiliation: Department of Physiology, School of Medicine, University of Tokushima, Japan.
authors.forename: Z L
authors.initials: ZL
authors.lastname: Jiang
authors.forename: J
authors.initials: J
authors.lastname: He
authors.forename: H
authors.initials: H
authors.lastname: Miyamoto
authors.forename: H
authors.initials: H
authors.lastname: Tanaka
authors.forename: H
authors.initials: H
authors.lastname: Yamaguchi
authors.forename: Y
authors.initials: Y
authors.lastname: Kinouchi
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity; D017536:Carotid Artery, Common / Q000502:physiology*; D003971:Diastole; D004242:Diving / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D007101:Immersion; D008297:Male; D013550:Swimming / Q000502:physiology; D013599:Systole; D013997:Time Factors