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Updated: May 17, 2026

Training Rats to Voluntarily Dive Underwater: Investigations of the Mammalian Diving Response
Published on: November 12, 2014
Referral patterns and outcomes of dive medical examinations in a tertiary hyperbaric facility
Lin Min Ong1, Michael H Bennett, Paul S Thomas
1Sixth-year medical student at the Prince of Wales Clinical School, Faculty of Medicine, University of New South Wales. This paper was presented for her 'Independent Learning Project' in 2008.
Introduction:
Scuba diving involves risks, and candidates in Australia usually have a medical evaluation prior to undertaking a diving course. Hyperbaric physicians act as secondary referral practitioners for these assessments. This study aimed to identify reasons for these secondary referrals, and document the assessment process and outcome for potential dive candidates.
Methods:
This was a retrospective case-note analysis of candidates for dive medicals presenting to the Department of Diving and Hyperbaric Medicine (DDHM) at the Prince of Wales Hospital, Sydney, over 10 years.
Results:
We identified a total of 191 candidates aged 12 to 67 years. Most were candidates for recreational diving (n = 148, 77.5%) and 119 (62.3%) were male. Commercial dive candidates had higher median total number of dives (P = 0.005), median maximum depth (P < 0.001) and median years, diving (P = 0.018) than recreational dive candidates. Respiratory problems were the most common referral reason for presentation (35%), followed by CNS (14%), ENT (13%) and cardiovascular conditions (9%). Most candidates were assessed as 'fit to dive' (136 or 71%), 49 (26%) were 'unfit', while six (3%) were subject to restrictions. Forty-three candidates (22%) presented with a diagnosis of asthma, of whom 25 (13%) were considered 'fit to dive'.
Conclusion:
The most common presentation for evaluation was for respiratory conditions, particularly asthma, but a wide range of medical conditions were assessed, and subjects were evaluated on an individual basis. Although current standards in Australia discourage asthmatic subjects from diving, over half of the candidates presenting with a possible diagnosis of asthma were assessed as 'fit to dive'.
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