title: Effect of hyperbaric pressure during scuba diving on autonomic modulation of the cardiac response: application of the continuous wavelet transform to the analysis of heart rate variability.
abstract: This study sought to determine the effects of hyperbaric pressure on heart rate modulation, by analyzing potential changes in heart rate variability (HRV). Ten divers were exposed to pressures of 1, 2, 3, and 4 atmospheres absolute (ATA). The test was performed in a hyperbaric chamber. Heart rate (HR) was recorded in supine subjects for 10 minutes per atmosphere. HRV was analyzed in the frequency mode (fast-Fourier transform and continuous wavelet transform). Results confirmed bradycardia as pressure increased. The drop in HR attained statistical significance after 2, 3, and 4 ATA. Signal energy (normalized TP values) rose progressively, becoming significant at 2 ATA. High frequency and low frequency displayed similar behavior in both cases. Although frequency band peaks did not yield clear results, continuous wave transform analysis showed that the frequency spectrum tended to shift into the high-frequency range as pressure increased. In summary, increased pressure prompted increased bradycardia, and HRV shifted into high-frequency range.
authors.affiliation: Universidad de Las Palmas de Gran Canaria, 35017 Las Palmas de Gran Canaria, Spain.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Barbosa
authors.forename: Juan M
authors.initials: JM
authors.lastname: García-Manso
authors.forename: Juan M
authors.initials: JM
authors.lastname: Martín-González
authors.forename: Samuel
authors.initials: S
authors.lastname: Sarmiento
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Calderón
authors.forename: Marzo E
authors.initials: ME
authors.lastname: Da Silva-Grigoletto
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001274:Atmospheric Pressure; D004242:Diving / Q000502:physiology*; D005260:Female; D006329:Heart Conduction System / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D006931:Hyperbaric Oxygenation; D008297:Male; D012815:Signal Processing, Computer-Assisted