• As the depth increase, the air that is breathe gets denser. More effort is needed to breathe in and out. The heart would also need to work harder by pumping at a greater strength than what it is normally used to.
• The dense cool air under pressure can also cause problems to the sinuses and to the lungs especially those that have a history of asthma (even childhood asthma) or rhinitis (running nose). Some of these problems can be life threatening:

1. Pulmonary barotrauma
2. Cerebral air gas embolism
3. Sinus barotrauma
4. Aural barotrauma

• The underwater environment presents the diver with a weightless environment, up and down can be difficult to discern, sounds and vision are distorted, added to this is the disorientating effects of nitrogen narcosis.
• As such the underwater environment can be disorientating particularly at night. And someone who is anxious, it can be particularly worrisome.
• A proper meical screening and education is able to allay the fears of new diver and increase his enjoyment and appreciation of diving and make him want to come back for more.