title: Rapid ascent and buoyancy problems among Western Australian certified recreational divers.
abstract: BACKGROUND
  We investigated risk factors associated with ascending rapidly and/or losing buoyancy control among recreational divers.
  
  
  METHODS
  Dive and diver information were collected and depth/time loggers attached to recreational divers. Case dives recording an ascent > 18 m per min were compared with control dives made at the same dive site and time by divers recording ascents ≤ 18 m per min. In a second analysis, case dives with reported buoyancy problems were compared with control dives during which no problems were reported. Conditional logistic regression identified factors significantly associated with ascending faster than 18 m per min or reporting a buoyancy problem.
  
  
  RESULTS
  In total, 1,032 dive profiles were collected. Case dives (n = 71) recording an ascent > 18 m per min were compared with 282 control dives. The main risk factor for making a rapid ascent was a loss of buoyancy control. Case dives were also shorter. Dives resulting in reported buoyancy problems (n = 68 cases) were compared with 320 control dives. The three main risk factors for buoyancy problems were an inability to describe how to check for neutral buoyancy, reportedly not being in control during the final ascent and maximum ascent rates that were a mean of 20% faster than during control dives.
  
  
  CONCLUSIONS
  Further research is necessary to identify if ascending rapidly is the result of a loss of buoyancy control, a lack of ascent rate reference or a failure to appreciate the potential consequences of ascending rapidly. The inability of many divers to describe how to check for neutral buoyancy also deserves attention.
authors.affiliation: School of Sports Science, Exercise and Health, The University of Western Australia, Bunbury, WA 6230, Australia. reefdiving@eftel.com.au
authors.forename: Peter
authors.initials: P
authors.lastname: Buzzacott
authors.forename: Terri
authors.initials: T
authors.lastname: Pikora
authors.forename: Michael
authors.initials: M
authors.lastname: Rosenberg
authors.forename: Jane
authors.initials: J
authors.lastname: Heyworth
mesh_terms: D000054:Acceleration / Q000009:adverse effects*; D016022:Case-Control Studies; D002568:Certification; D004242:Diving / Q000009:adverse effects* / Q000502:physiology / Q000592:standards; D006801:Humans; D009038:Motion; D015999:Multivariate Analysis; D011998:Recreation; D012016:Reference Values; D012307:Risk Factors; D013997:Time Factors; D014904:Western Australia; D016526:Workload