Apparently it’s to help deal with how oxygen and nitrogen can both have a bit of a narcotic effect at high pressures. Helium doesn’t do this and is generally harmless to breathe so long as you’re still getting enough oxygen, so if some or all of the nitrogen is replaced with helium then it can mitigate the problem by reducing the amount of nitrogen you’re breathing
Anyone know why they use helium too?
Apparently it’s to help deal with how oxygen and nitrogen can both have a bit of a narcotic effect at high pressures. Helium doesn’t do this and is generally harmless to breathe so long as you’re still getting enough oxygen, so if some or all of the nitrogen is replaced with helium then it can mitigate the problem by reducing the amount of nitrogen you’re breathing