system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why did humans develop the cold shock response?

Humans automatically hyperventilate when they are exposed to very cold waters. In fact, the "cold shock response" is the leading cause of death for immersion in cold water. Why and how did we develop this as humans? Wouldn't a response like this decrease fitness and be harmful?
gpt
Strangely enough, the shock reflex is not the full story. There is also the diving reflex—when a vertebrate’s face gets wet, their heart rate slows, breath slows, and blood is shunted to brain and organs and away from extremities. The point is there are a variety of reflexes—quick inhalation of oxygen in anticipation of not having enough, flowed by conservation of oxygen. The combination has evolutionarily proven to be the best chance of survival, even though in some
circumstances it isn’t the best.