title: Effects of severe hyperbaric pressure on autonomic nerve functions.
abstract: Autonomic nerve functions under severe hyperbaric pressure were evaluated by measuring heart rate variability (HRV) and catecholamine excretion rate in 16 normal volunteers in submarine experimental facilities simulating conditions 330 m below sea level. HRV and urinary catecholamine levels were evaluated to assess sympathetic and parasympathetic tone. High-frequency HRV increased from 5.6 +/- 1.3 to 6.3 +/- 1.4 ms2 (p < 0.05), and SD of the average normal R to R intervals for 5-minute index (SDNNI) (time domain HRV parameter) increased from 77.2 +/- 32.7 to 93 +/- 33.8 ms (p < 0.05) after 3 days. Adrenaline/creatinine increased by 18% from a basal value of 4.04 +/- 0.44 ng/dL/h. Also, there was significant negative correlation between high-frequency and urinary cathecholamine levels. Evaluation of autonomic nerve functions under hyperbaric conditions by measuring HRV was shown to be a useful method. Thus, the present results indicate that the autonomic nerve functions of people who work under deep-sea conditions can be evaluated adequately by measuring HRV.
authors.affiliation: National Defense Medical College, Division of Biomedical Engineering, Tokorozawa, Saitama, Japan. kurita@res.ndmc.ac.jp
authors.forename: Akira
authors.initials: A
authors.lastname: Kurita
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Nagayoshi
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Okamoto
authors.forename: Bonpei
authors.initials: B
authors.lastname: Takase
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Ishizuka
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Oiwa
mesh_terms: D000328:Adult; D001274:Atmospheric Pressure; D001341:Autonomic Nervous System / Q000502:physiology*; D002395:Catecholamines / Q000652:urine*; D004242:Diving / Q000502:physiology*; D006339:Heart Rate; D006801:Humans; D008297:Male; D008889:Military Personnel; D009326:Naval Medicine
chemical_list: D002395:Catecholamines