The Norseman Departure: Navigating the Cold Waters of Eidfjord
I’ve taken the Norseman departure ferry more times than I can count. The boat leaves the Eidfjord pier around four in the morning. It’s dark. It’s cold. 250 athletes in wetsuits shuffle around the car deck, trying to stay calm. And at one point, before they jump four meters into the fjord, we spray them with cold water.
A lot of people think it’s theater. A sort of awakening ritual. It’s not. We do it because the first sixty seconds in the cold water are the most dangerous minute of the entire race. Spray is one of the best ways I know to make this minute less dangerous.
The Real Danger: Cold Shock vs. Hypothermia
When people ask me what kills in cold water, they expect me to say hypothermia. But hypothermia is slow. The real killer is much faster and usually strikes before you’ve even started swimming. Let me try to explain why and what you can do about it.
As soon as cold water touches bare skin, your body panics. The nerves in your skin send a huge alarm signal to the brain and heart. You gasp. You are hyperventilating. Your heart rate increases. Your blood pressure rises. All this in seconds.
Michael Tipton described this sequence in 1989, and it hasn’t really changed since. The first breath alone represents two to three liters of air, sucked in uncontrollably in the first second after hitting the water. If your face is underwater at this time, you are not breathing air. You breathe water. This is how strong pool swimmers drown ten meters from a boat.
The Autonomous Conflict
At the same time, the opposite reflex is triggered. Cold water on the face, combined with holding your breath, triggers what is called the diving response. Your heart slows down. The blood vessels in your arms and legs close. It’s a very old reflex. All mammals that dive underwater are affected, from seals to humans.
By itself, the diving response is harmless. In itself, the cold shock response is unpleasant but allows survival. The problem is when they happen at the same time.
In 2012, Mike Shattock and Mike Tipton gave this problem a name: autonomous conflict. Here’s what’s happening. The cold shock response tells the heart to speed up, now. The diving response tells the heart to slow down, now. Both signals are maximum. Both arrive at the same time.
The heart doesn’t know what to do. In this confused moment, it can jump. It can float. In the worst cases, it can progress to a dangerous rhythm called ventricular fibrillation. And this can happen in a perfectly healthy heart. This is the part that is hard to accept. The victim is not always the one with a weak heart.
Reducing Risks
The risk increases if you have a known heart condition, are older, have had a drink, or jump face first while holding your breath. This last combination is the worst I know.
Most cold water deaths occur within the first three minutes. Not in the middle of the fjord. Not halfway across the Channel. The first three minutes. The body cools slowly. This is not the case with the nervous system. This is why ports, piers and ferry decks are overrepresented in mortality statistics, not open waters.
The dangerous place is the edge.
The good news is that this whole stunt can be blunted, and the evidence for how to do it is actually quite clear.
Practical Tips for Safe Cold Water Swimming
Don’t jump. Enter. First spray your face and neck. Let your skin feel the cold for 30 to 60 seconds before putting your head under it. The breath will be much smaller.
Get used to it. Five or six short swims in cold water over a few weeks will reduce the cold shock response by about half, and the effect will last for months. This is probably the most underutilized safety intervention in open water swimming.
Dress for water, not air. A wetsuit, neoprene hat and maybe some slippers aren’t just for staying warm while swimming. They cover the skin where the cold shock response begins. Less exposed skin means a lower alarm signal.
Never swim alone and keep safety boats within reach. It is possible to survive most cardiac events in cold water if someone can reach you within the first minute.
Know your heart. If you have a known heart condition, think twice before you start. Think three times if you are over 40. I’ve written this in every Norseman race file for years, and I will continue to write it.
The Norseman Ritual: Preparation and Respect
Return to the ferry at Eidfjord.
The departure of the Norseman is, on paper, almost the worst possible entry into cold water. Dark. Cold. A four meter jump. 250 people go there at the same time. Adrenaline through the roof. If I were trying to design a scenario to trigger a standalone conflict, I couldn’t do much better.
So we spray the athletes on deck first.
Standing on the deck of the car, in a suit, the athlete feels the cold hitting his face and neck. The cold shock response begins. The breath comes. Breathing becomes rapid. Heart rate increases. And then, in twenty or forty seconds, everything works out. The nervous system is warned: the cold is coming. The next exposure, about a minute later, when they reach the fjord, is much smaller. The breath is smaller. Breathing recovers more quickly. The collision between the two reflexes is less violent.
It’s physiology. But there’s also a psychological part, and I think that’s just as important.
The spray on the deck tells the athlete: this feeling is expected. It’s short. It’s not an emergency. Panic is what turns cold water gasping into drowning. Removing the surprise removes most of the panic.
We’ve been doing this for years now and I still think it’s one of the most important minutes of the entire race.
The Cold Water Experience
Cold water is not dangerous because it is cold. It’s dangerous because of what your nervous system does from the first minute of contact. Respect this minute. Prepare for this. Don’t think of this as the easy part of swimming.
If you do this, cold water will stop being deadly. This becomes one of the best training tools we have.
Don’t jump in. Enter. And if you really have to jump off a ferry, at five in the morning, in a Norwegian fjord, let someone spray you first.
I actually wrote a book about it – and about cold water swimming in general.
I wrote it because I think everyone deserves some calm, trustworthy advice before diving into cold water. The cold is worth experiencing. But it deserves your respect.
Get it here: Cold Water Swimming – A Mini-Book
• Tipton MJ. Early responses to cold water immersion in humans. Clinical Science 1989; 77:581-588.
• Shattock MJ, Tipton MJ. “Autonomous conflict”: another way to die in cold water immersion? Journal of Physiology 2012; 590(14): 3219-3230.
• Tipton MJ, Collier N, Massey H, Corbett J, Harper M. Cold water immersion: kill or cure? Experimental Physiology 2017; 102(11): 1335-1355.
• Work by our Norseman research group on cold water swimming, body temperature regulation and wetsuit use in triathletes.
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