Wreck Diving
then attempt deep dives with unstable health conditions. If people had health problems during wreck dives momentary panic may lead to a heart attack.
Attitude is equally critical when it comes to staying safe underwater. People in some way loose their sense of reality especially with the hint of retrieving a priceless artifact from a dive, an ego drive.
Sudden Diver Death Syndrome
Found floating but without any indication of drowning, a subsequent autopsy reveals no heart problems or other cause of death. For all intents and purposes, the individual fell over dead. This "Sudden Diver Death Syndrome" is not very well known either within the medical community or the public in general. The victims are typically in their mid-30s or older and are struck down in the spring following a winter of relative inactivity. It's thought that death results from cold-water immersion causing heart arrhythmia
Hypothermia
The waters off eastern Australia range in temperature from the mid-40s to the high-50s. By any human measure, that's cold water. Immersed in this water without any thermal protection dooms a typical victim within a few minutes, at most.
According to the Divers Alert Network about 100 people are killed while scuba diving each year and about 1,000 more are injured. Experts contend that a majority of these deaths and injuries result from unsuitable divers who receive inadequate scuba training. Still, the number of diving deaths is low, considering the many other ways that people lose their lives.
Two to three day courses often offered at tropical resorts present countless safety risks, which can be easily avoided by taking the standard six-week scuba program. The training received at the resort is good enough if you wanted to learn how to snorkel, but if you're going down where your lungs can blow up if you do anything stupid, there's obviously something wrong with the shorter classes.
A diver's physical safety isn't all that the two to three day courses put into jeopardy, resort certification courses also don't prepare divers psychologically. Emotions typically restrict or prevent rational thought. If someone who has not been taught to control their emotions underwater has a problem while diving, and can't solve it because of fear or panic, then that problem can quickly become deadly.