Nitrogen - effects during diving when descending and at depth

• until a depth of about 30 m is reached an increasing partial pressure of nitrogen has minimal effects on most people
  • as depth is increased, divers who dive on air will experience increasing symptoms of nitrogen narcosis (the "narks") and, if they carry on diving deeper, they will eventually exhibit signs of narcosis
    • initial signs are:
      • an increase in reaction time
      • inability to deal with a given situation and clumsiness
  • cure for nitrogen narcosis is to ascend

Notes:

• the aetiology of nitrogen narcosis is because nitrogen is thought to act in a similar manner to an anaesthetic and may interact with, or alter the three dimensional structure of various neurotransmitter receptors
• a method to avoid nitrogen narcosis is to replace some or all of the nitrogen with a gas that is less narcotic, such as helium

Reference:

• 1) Edge CJ. Recreational diving medicine.Current Anaesthesia Critical Care 2008; 19 (4): 235-246