Technically speaking, Ross says, anything below 5 degrees Celsius is considered ice swimming, and contrary to popular belief, cold water shock is the biggest danger, not hypothermia. The trick, he explains, is to acclimatize to the cold water before starting your physical exertion.
The pair strip down to their swimmers, and do some running to get the heart going, before hitting the water. As soon as Matt has jumped in, Ross talks him through his breathing, as the “gasp reflex” is what causes people to hyperventilate. They spend two minutes at rest in the water while Matt gets used to the cold; he dips his face under the water to instruct his body to constrict the capillaries around his hands and his feet.
“Now we’ve basically started the stopwatch on hypothermia,” Ross says after that two-minute period. “It’s now very important that we start moving to generate heat.”
After four minutes of breaststroke out to a buoy and back, Ross conducts a quick dexterity test to ensure Matt can still control his fingers. “You’re talking, and you’ve got good dexterity,” he says, “let’s go again, front crawl… You’ve got to keep moving, the whole time you sit here you’re not generating heat.”
As soon as they’re out of the water, they dry off quickly, but the ordeal isn’t over: instead of heading inside, they set off on a 5 km run, barefoot through the Kent countryside. “This is the bit now where you get what’s called afterdrop,” Ross says. “What a lot of people want to do is get in a nice warm shower, but what will happen if you do that is all the blood will go back to your extremities, all the blood will leave your core and your vital organs. The only thing you’ve got to do now is start heating yourself up from the inside out.”
Unsurprisingly, by now Matt is finding the entire experience rather taxing. “My balls are killing,” he says at the end of the run. “That is the weirdest thing. Because my cardio is so bad, I was so tired… I was so tempted just to sink to the bottom… it was just so painful.”
“It’s cool doing things, crazy, out of your comfort zone things,” he continues. “It puts the rest of your life into perspective. It’s cool to do weird stuff.” He clarifies, though, that this is his first and absolute last experience with ice swimming, and that no amount of money would get him back into the water.