system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does an athlete using smelling salts work?
gpt
Smelling salts release ammonia gas. If you breathe in this gas, it irritates the insides of your nose and lungs to such an extent that it stimulates your sympathetic ("fight-or-flight") nervous system. This is an autonomous part of your nervous system that, when activated, has all sorts of arousing effects on your body, releasing adrenaline, increasing your heart rate, opening up your lungs, increasing blood flow to your skeletal muscles (while decreasing it to your digestive system), and generally preparing your body for action. For athletes, these effects may be desirable and performance-enhancing, although perhaps especially so for athletic feats that require quick bursts of action. Smelling salts have also been used to revive athletes that have been rendered unconscious (e.g. boxers), because their arousing effects counteract the fainting response.