title: Elevations in Intra-cranial blood flow velocities following a SCUBA Dive and the Influence of Post-dive Exercise.
abstract: The effect that a SCUBA dive has on cerebral blood flow (CBF) at rest and during exercise is poorly understood. We examined the hypothesis that the altered hemodynamic parameters following a SCUBA dive will lead to differential changes in CBF at rest and during exercise. 16 divers completed a field-based study with a single dive at a depth of 18 m sea water with a 47-min bottom time. A follow-up laboratory based study was conducted - 1 week later. Intra-cranial velocities were measured with transcranial Doppler ultrasound (TCD) pre-dive, post-dive at rest and throughout incremental exercise until exhaustion. Following the dive at rest, middle cerebral artery velocity (MCAv) was elevated 15 and 30 min after surfacing (by 3.3±5.8 and 4.0±6.9 cm/s, respectively; p<0.05); posterior cerebral artery velocity (PCAv) was increased at 30 min after surfacing (by 3.0±4.5 cm/s; p<0.05). During exercise following the dive, both MCAv and PCAv increased up to 150W followed by a decrease towards baseline at 180W (p<0.05). We found no difference in CBV during exercise between field and laboratory studies (p<0.05). The novel finding of this study is the transient elevation in resting intra-cranial velocities within 30 min following a SCUBA dive.
authors.affiliation: Faculty of Medicine, University of Novi Sad, Department of Physiology, Novi Sad, Serbia.
authors.forename: O F
authors.initials: OF
authors.lastname: Barak
authors.affiliation: University Hospital Centre Split, Department of Neurology, Split, Croatia.
authors.forename: K
authors.initials: K
authors.lastname: Caljkusic
authors.affiliation: University of Split School of Medicine, Integrative physiology, Split, Croatia.
authors.forename: D
authors.initials: D
authors.lastname: Madden
authors.affiliation: University of British Columbia, Okanagan Campus, Kelowna, British Columbia, Centre for Heart, Lung and Vascular Health, Kelowna, Canada.
authors.forename: P N
authors.initials: PN
authors.lastname: Ainslie
authors.affiliation: Faculty of Medicine, University of Novi Sad, Department of Physiology, Novi Sad, Serbia.
authors.forename: D
authors.initials: D
authors.lastname: Slavic
authors.affiliation: University Hospital Centre Split, Department of Neurology, Split, Croatia.
authors.forename: A
authors.initials: A
authors.lastname: Buca
authors.affiliation: University of Split School of Medicine, Integrative physiology, Split, Croatia.
authors.forename: Z
authors.initials: Z
authors.lastname: Dujic
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity; D002560:Cerebrovascular Circulation / Q000502:physiology*; D004242:Diving / Q000502:physiology*; D004452:Echocardiography; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012146:Rest; D018608:Ultrasonography, Doppler