system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do we get this "spacey" feeling right before we sneeze?

You lean your head back a little, you close your eyes, no thoughts are going through your head (spacey, lightheadedness), then BAM. You sneeze. What causes that feeling?
gpt
A sneeze is an involuntary action but it is a semi-autonomous one, meaning you have some degree of control over it. Most of the time, though, you don't choose to exercise this control and resign yourself to the action. It's similar to a yawn- you feel your own body doing something on its own accord. Additionally, your breath fluctuates wildly during a sneeze and especially during multiple sneezes. This combination-  your conscious brain experiencing an unconscious action plus a change in your regulation of oxygen- creates a "disconnected" feeling that leaves you feeling discombobulated after a sneeze, as if you're "returning to reality".