Czarna Góra, Poland - Out in the icy waters of Poland, one swimmer achieved a feat most would think not only impossible, but deadly dangerous. He swam the longest ice swim in history, and lived to tell the tale.

Swimming in ice-cold water sounds like a truly terrible, and extraordinarily dangerous, idea.

Yet, one man decided that he would not only take the plunge, but stay in the water for so long that you wouldn't expect him to come out alive.

This is the story of the longest ice swim in history, and it's remarkable.

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Who is this mystery man, this world record setter and ice swimmer? How did he survive swimming four miles in water that's near-freezing, and what were the requirements he had to meet to attain the award?

On the 19th of April 2023, Krzysztof Gajewski went for a long swim in a lake in Gzarna Góra near Sienna, Poland, but it was no normal swim. When he emerged he was not only freezing cold and profoundly tired, but the remarkable holder of a world record very few had attempted and even fewer had held.

Krzysztof Gajewski had managed to accomplish the longest "ice swim" in history having swam 3.7 miles over the course of one hour and 46 minutes in water that was below 40.7°F. The standard rules set out by the International Ice Swimming Association (IISA) define an "ice swim" as one that is undertaken in water below 41°F while wearing a swim cap, goggles, and a standard swimsuit. As he met these parameters, he became the record holder.

Interestingly, Gajewski was not only scoring himself a world record, but beating his own. A mere month before the swim, on March 12, he swam 3.1 miles in similar conditions near Wrocław, Poland. Of course, in both cases, Guinness World Records was quick to check the facts, award the reward, and post the information on their website.

It's a pretty shocking record to have achieved. The human body will quickly start to fail as its core temperature gets below 98°F, so it's curious how ice swimmers can stop this from happening.

There are few things more dangerous than serious long-distance ice swimming. It's an extreme sport that truly deserves the title of "extreme," and one that is tightly controlled and regulated by the IISA. We would not recommend giving it a go without an instructor and plenty of training beforehand, however, there are a few fundamental concepts that likely aided Gajewski in his quest.

According to the United States Masters Swimming (USMS), a nonprofit that supports swimmers across the USA, in order to swim in dangerously cold water like Gajewski did he would have had to acclimatize himself to such temperatures over much of his life. This means that he likely has been swimming in freezing cold water like this regularly for years.

The trick, apparently, is to build up to the long lengths of time that it would take to swim such distances – Gajewski was in the water for almost two hours – by gradually increasing the amount of time you spend swimming. He likely raised his body temperature in a sauna before going in as well, to lengthen the amount of time his body could take to cool down.

Ultimately, other than that it is just about perseverance and being as safe as possible. In the video, you can see that he is always close to the edge and is clearly visible at all times. He would have had many people watching, ready to dive in and save him if necessary.

Most people would be dead if they swam in such cold water for as long as Gajewski did in his world record attempt. As you swim in such water, your body temperature will reduce further and further until it is well under the level it should be and your internal organs start to shut down.

If you tried to do this without some serious training and a lot of practice, it wouldn't take much longer than 10-15 minutes for this process to be complete and for you to die. Seriously – if you value your life, don't try this at home.