When someone inhales nitrous oxide, the gas rapidly dissolves into the bloodstream, and hits the brain within seconds. Effects vary between people and are rarely quite the same twice, but a rush of dizziness and euphoria is normal, and people often burst out laughing. Sound is oddly distorted, voices and music often turning into a throbbing roar like a helicopter.
Hallucinations are possible, from simple moving bright dots to complete detailed dreamscapes, although most users do not experience complex hallucinations. The gas is an anaesthetic, so coordination and awareness are strongly affected and users may fall over if they are not sitting or lying down. The experience ends almost as swiftly as it began, with the peak lasting just seconds and the user back to normal within about 2 minutes. Sometimes, people take many ‘hits’ of nitrous oxide over a few hours. Nitrous oxide also reduces anxiety and pain.
Additionally, when inhaled recreationally in the usual (and least risky) way, from a balloon, the gas in the lungs displaces air, temporarily preventing much or any oxygen getting into the blood. This may cause the heart to beat faster, and limbs to feel tingly or heavy.