Real World vs Lab Test
Cold shock is far more intense in real life than in scientific research experiments.
The Real World
As soon as they’re in the water, people immediately realize that they’re fighting for their lives.
They’re unfamiliar with cold water.
They’re surprised and stunned.
They know they’re in desperate trouble.
They’re terrified of dying.
Shivering in a physiology lab's 55F (13C) pool
Extreme Environments Laboratory / School of Sport, Health & Exercise Science / University of Portsmouth, United Kingdom
The Lab Test
The people who participate in scientific cold shock experiments are relaxed volunteers.
They’re familiar with cold water.
They know in advance what’s going to happen.
They know they’re not in any real danger of drowning.
They're not afraid.
Nevertheless, despite all that reassurance, they experience cold shock for two – three minutes, and it can take up to five minutes for them to stabilize their breathing at around twice the pre-immersion level.
Randy Morgart's Experience
In a November 2011 article published in Sea Kayaker magazine, Randy Morgart recounted a near-death incident in which he capsized in 32F water on the Mississippi River.
He wasn’t wearing a wetsuit or drysuit and spent 10 terrifying minutes in the water before he was finally able to self-rescue using a paddle float. It was a desperate, life or death situation, and he barely made it back into his kayak on his third and final try.
He reported that 15 minutes after he reentered his kayak, he was still hyperventilating due to cold shock.
“I noticed my vision getting dark around the edges and a roaring in my ears that almost covered the usual river noises.”
In other words, the darkness was closing in as he struggled to paddle back to the boat ramp. That’s a classic symptom of hyperventilation syndrome and it was still a threat 25 minutes after he capsized.