 The most straightforward way to avoid nitrogen narcosis is for a diver to limit the depth of dives . Since narcosis becomes more severe as depth increases , a diver keeping to shallower depths can avoid serious narcosis . Most recreational dive schools will only certify basic divers to depths of 18 m ( 60 ft ) , and at these depths narcosis does not present a significant risk . Further training is normally required for certification up to 30 m ( 100 ft ) on air , and this training should include a discussion of narcosis , its effects , and cure . Some diver training agencies offer specialized training to prepare recreational divers to go to depths of 40 m ( 130 ft ) , often consisting of further theory and some practice in deep dives under close supervision . Scuba organizations that train for diving beyond recreational depths , may forbid diving with gases that cause too much narcosis at depth in the average diver , and strongly encourage the use of other breathing gas mixes containing helium in place of some or all of the nitrogen in air – such as trimix and heliox – because helium has no narcotic potential . The use of these gases forms part of technical diving and requires further training and certification . 
