Let's say I buy a bottle of helium with approximately 50 L at a pressure of approximately 300 bar. Unser normal air pressure that would be approximately 15 m^3 of helium. So far that's okay and corresponds to the vendor's data.

But now for the practical implications:
Upon opening the valve, how quickly does the gas expand and adjust to normal air pressure?

Assuming I want to inhale the gas, is there a risk that it might destroy my lungs due to too high pressure? Would I have to use another tool to regulate the pressure in order to avoid mechanical damage? If so, what is the easiest way to do so?