We test the longstanding hypothesis, known as the dive constraint hypothesis, that the oxygenation demands of diving pose a constraint on aquatic mammal brain size.Using a sample of 23 cetacean species we examine the relationship among six different measures of relative brain size, body size, and maximum diving duration. Unlike previous tests we include body size as a covariate and perform inde...

We report a case of retinal vein occlusion after breath-holding diving. After one hour of diving at a maximal depth of eight meters, each apnea no longer than one minute, the patient complained of a diminution of the visual acuity in the left eye. Ophthalmological examination revealed an occlusion of the superior branch of the central vein of the retina in the left eye. This could be considered...

This study has explored perceived crowding of an underwater environment. Two dimensions were assessed: the number of divers seen and the proximity of divers to each other. Data were obtained from a survey of 216 divers who undertook diving in Hong Kong during 2013e14. Photographs depicting four levels of crowding (number of divers) and four levels of diver proximity in different combinations we...

Middle ear barotrauma is one of the common complications of SCUBA diving representing acute otalgia, hearing loss, and bleeding. But occurrence of facial palsy is rare. Here we report a case of a 30-year-old navy diver suffered middle ear barotrauma with transient facial palsy after SCUBA diving. He felt difficulty in equalizing the pressure in middle ear with Valsalva maneuver during diving, a...

When diving, human beings are exposed to hazards that are unique to the hyperbaric underwater environment and the physical behavior of gases at higher ambient pressure. Hypercapnia, hyperoxia, carbon monoxide intoxication, inert gas (predominantly nitrogen) narcosis, and decompression illness all may lead to impaired consciousness, with a high risk of drowning in this non-respirable environment...

Recreational scuba diving is a sport that requires a certain physical capacity, in addition to consideration of the environmental stresses produced by increased pressure, low temperature and inert gas kinetics in tissues of the body. Factors that may influence ability to dive safely include age, physical conditioning, tolerance of cold, ability to compensate for central fluid shifts induced by ...

Linking deep stop model and data, we detail the LANL reduced gradient bubble model (RGBM), dynamical principles, and correlation with the LANL Data Bank. Table, profile, and meter risks are obtained from likelihood analysis, and pertinent applications include nonstop air diving, the Bennett and Maronni 2.5 minute recreational deep stop, C & C Team 450/20 multiple RB dive sequence at 1.4 atm, NE...

This study examines and extends the empirical evidence of the causal relationships among experience, personality and attitude on the behaviour of scuba divers. The empirical data were collected from divers (n 1⁄4 413) in the five most popular islands for scuba diving in Malaysia. Measurements of diving attitude, experience and underwater behaviour were developed based on the literature and expe...

Hyperbaric oxygen therapy is a noninvasive therapy used in the treatment of diving-related medical illnesses. It is an important adjunct in the management of a variety of medical conditions. The Republic of Singapore Navy Medical Service (NMS) is the main driver of the development of hyperbaric and diving medicine in Singapore. The practice of hyperbaric medicine has inherent risks, and unregul...

Background: A number of occupations and professions may be associated with unique hazards relevant to urologic care. Case Presentation: We relate the presentation, care, and the occupational hazard of urinary tract infection (UTI), presenting as cystitis and pyelonephritis, with stone formation in a scuba diver. The patient voiced concern that his diving suit malfunction was related to his UTI ...