Why is helium used in diving apparatus?

(N/A) Air contains a large amount of nitrogen,and the solubility of gases in liquids increases with an increase in pressure. When sea divers dive deep into the sea,a large amount of nitrogen dissolves in their blood. When they come back to the surface,the solubility of nitrogen decreases,and it separates from the blood,forming small air bubbles. This leads to a dangerous medical condition called bends. Therefore,the air in oxygen cylinders used for diving is diluted with helium gas. This is done because $He$ is sparingly soluble in blood.