“Take a deep breath in,” bellows the Iceman, Wim Hof. “And let it go. Fully in … and letting go. Get into your rhythm, fully in, letting go …”

Lying on his sofa, I do what he says: a big breath in, then release, 20 more, nine more, four, here comes the last.

“And stop, close your mouth, easy does it, just stay relaxed and witness. You are without air in your lungs, we will do one minute.”

And we – I – do, hold my breath for a minute. “Three, two, one, fully in, squeeze it a little bit to your head, this is bringing cerebrospinal fluid to the brain, letting go. Now we go again.”

So off we go again: 40 full breaths, exhale, then hold it, this time for a minute and a half. Hof says my blood chemistry is changing. I feel a bit tingly, hear a slight ringing noise, but I can do it, a minute and a half, he times it on his phone. I’ve never held my breath for that long.

We do another round of breathing, then I hold it for two minutes. He says there’s more adrenaline rushing through my system than there would be if I was doing a bungee jump. “This is real science,” he says. I had put it to him that some of his claims are quite bold, and that he has his critics. We’ll come back to that. Right now I’m just focusing on my breathing.

And one more time, two and a half minutes without breathing. He talks as I hold it, and says my body is bringing down inflammation. I told him I had some osteoarthritis in my hand; this will help, he says, optimistically. I also told him I’d had depression. He says this helps depression as well. “You’re dealing with the chemical residue that causes the anxiety, you are cleansing the shit. And, yes, it improves the virility as well.” I don’t think I said I had any issues with my virility, did I?

I’m feeling relaxed, calm, a little bit trippy. “Yes, I always say: ‘Get high on your own supply.’” He likes a catchphrase. “A cold shower a day keeps the doctor away,” is another; and “We go, no ego.”

That last one grates a little. I’m no expert but I’d say that Hof’s ego is in pretty good health. He is full of stories starring Wim Hof as the hero. My favourite is one about leading a group of people up a mountain in the Spanish Pyrenees. They got to the hut where they were spending the night; Hof realised they had forgotten to bring the food, so he went back down, made Spanish tortillas and brought them back up for the group. But still he was full of energy, so he ran on up to the top of the mountain, overtaking a mountain goat on the descent. “I think the animal respected my animalistic energy. Normally, it takes eight hours to go up and back, I did it in one hour and a quarter.” He actually out-mountain-goated a mountain goat.

Anyway, ego or no, now we go, to the garden, where he has a barrel of icy water ready …

Hof is a stuntman, an extreme athlete and now a wellness guru with a primetime TV show (Freeze the Fear With Wim Hof, on BBC One). He has set records for swimming under ice, for sitting in a box full of ice, for running barefoot on ice. He regularly climbs Kilimanjaro – and got a fair way up Everest – half naked. His techniques – which combine hypoxic breathing, cold water and willpower to make the Wim Hof Method or WHM – have been adopted by athletes, Silicon Valley entrepreneurs and celebrities. He has trained Twitter’s Jack Dorsey, Oprah Winfrey and Orlando Bloom. Now, it seems everyone is getting involved. “One hundred million people know my methods,” he boasts. There have been 40m downloads of his Breathing Bubble audiovisual guide. It has struck a chord during the Covid pandemic, he says, because it’s about tolerating discomfort. “I want to show the world there are ways to get hold of your own physiology.”

I’m spending the afternoon with him in the village of Stroe in the Netherlands, an hour from Amsterdam, where he does weekends and workshops of hypoxic breathing and ice baths. It’s a filthy day, cold and driving rain, but he comes out barefoot, in just a pair of shorts and a T-shirt, singing. He often breaks into song. At one point, he picks up one of his many guitars, this one a present from a fan who has inlaid it with ice crystals and a picture of Hof’s face. He plays and sings a song he wrote called Crazy Like a Monkey, although he’s forgotten some of the words. “Crazy like a money, yeah … fuck, yeah!” He plays well, and has a big powerful voice. Everything about Hof is big and powerful. And everywhere he goes he’s followed by his dog, Zina; he calls her “my brown shadow”.

Outside, he has created a kind of Disney paradise, with pools and rocks, palms and bamboo, plastic animals, flamingos, a lifesize rhinoceros. The noise from the busy motorway on the other side of the fence is a shame. There’s a tipi and a couple of yurts where guests can stay. He used to live in the house here, now he lives in Amsterdam with his second wife, Erin, and their four-year-old son, Eden, the youngest of his six children. He prefers it in Stroe, though. “Here, I jump from the rocks, I go into icy water, I do crazy stuff, I do my splits like a ballerina. I can’t do that stuff in an Amsterdam apartment. There, I have to behave, I’m not a behaving kind of guy,” he says. “I love her to death,” he adds quickly. Erin is 29 years younger than Hof, who’s 62. She was on one of his courses, that’s how they met.

Hof goes on long monologues, extolling the benefits of the WHM and generally bigging up WH. He can control his core body temperature, prevent it falling to dangerous levels of hypothermia when exposed to the cold. He says he can manage the part of his nervous system that is responsible for breathing and heart rate, as well his adrenaline, dopamine and serotonin. And that we have control over our immune systems and our anxieties, and the power to prevent illness, depression and inflammation.

He does have some backup from science. In 2014, a comparative study in the Netherlands found that 12 people trained by Hof and then injected with E coli had milder flu-like symptoms than an untrained control group. A 2019 study of 13 people with spinal arthritis found a decrease in inflammation over eight weeks of breathing and cold water training. In San Francisco, Elissa Epel, a professor in the psychiatry department at the University of California, is leading a study comparing the stress-relief effects of low-intensity meditation, exercise and Hof’s breathing method.

But listening to Hof, you would think the WHM was a miracle cure for pretty much everything. And when he starts talking about doctors, that many of them don’t want to heal but are “drug-pushers”, he starts to sound conspiratorial.

His critics say he’s bold with his claims and he overstates what his methods can do. Wouter van Marken Lichtenbelt of Maastricht University has said Hof’s scientific vocabulary is “galimatias”, or nonsense. “With conviction, he mixes, in a nonsensical way, scientific terms as irrefutable evidence.”

Of the doubters, Hof says: “They can doubt, but let them try this once before they end up in the dead end of their own prejudice.”

We’re in the kitchen now. Hof offered coffee but then it was forgotten, lost in monologue. His eldest son, Enahm, drops in and re-offers, apologising for the instant coffee. His dad is a terrible cook, he says; when they were kids, he would give them pasta with tomato ketchup. Hof eats once a day, simple food, vegetables. Leeks are a favourite, with salt.

Enahm, 37, along with three of his siblings, runs the business – the events, keynote speeches, website, training, merchandise. It must be fabulously profitable. “There is no problem financially now,” says Hof. “But what is important is my health and my children’s health, physical and mental, and that is not dependent on money.”

It can be dangerous, people have died doing the WHM. Enahm steps in on this one. People have seen his dad’s records, diving under ice, which has nothing to do with the WHM, he says, but they relate them. “One of the most common deaths among experienced swimmers is shallow water blackout: people get over-oxygenated, pass out underwater and drown,” he says. “What happened here was people practising Wim Hof Method tried breathing techniques and then went diving, not in cold water, but in lukewarm water, and they passed out.”

Hof agrees, it had nothing to do with the method. But now there are warnings all over the place, on the website, on downloads. The breathing can cause lightheadedness, loss of consciousness. It’s not meant for people who have certain medical conditions.

Hof’s own life has been punctuated by near-death experiences, tragedy and epiphany. He almost didn’t make it into the world. After his identical twin brother, Andre, was born, their mother was taken to recover; no one knew there was another baby. “I almost suffocated, I came out purple,” he says. His mother, a devout Catholic, cried: “Oh God, let this child live! I will make him a missionary!” Which he kind of is, although maybe not in the way she envisioned.

When Hof was seven, playing outside, he fell asleep in the snow. He became hypothermic, but was found just in time and recovered. Another time, he got very sick with a bacterial infection and nearly died. He wasn’t academic, but became interested in yoga, Hinduism, Buddhism. “I had this urge to find out deeper what is out there,” he says. He says the trauma of his birth was instrumental in making him who he is now.

When he was 17, walking in Beatrixpark in Amsterdam one Sunday morning, he saw the thin layer of ice on the surface of the canal and felt the urge to take off his clothes and get in. “So that’s what I did, I followed a hunch, and it was so great, I was playing with the ice and it was such an amazing sensation which afterwards stayed with me all day long and that made me decide to go back the next day and try it again.” The Iceman was born.

Hof met his first wife, Olaya, from the Basque country in Spain, while living in a squat in Amsterdam. Enahm was born, they became a family and got by on very little money. They had three more children and spent time living in a Basque village.

But Olaya’s mental health was suffering. She was depressed, and spiralled downwards. “Imagine the love of your life, the mother of your children, slipping away over the years, and you can’t do anything,” he says. In the summer of 1995, Olaya kissed the children goodbye and jumped from the balcony to her death.

Hof, in emotional agony, as well as facing bringing up four children himself with very little money, found some comfort in cold water, in the canyons around Pamplona. “I found that going into cold water stops whatever is going on in your mind, you’ve got to survive in cold water, it is merciless, but righteous.” It helped him heal, and he began to think it could help others heal, too. And the seeds of the Wim Hof Method were born.

Does he think it might have helped Olaya, I wonder? “Me knowing what I know now? I would get her out in no time.”

Now it’s my turn. Hof is going to activate my potential, he says, transcend my limits. What about igniting my awe of my body, my mind and my beautiful humanity? I want that as well (I’ve read the book, I’ve got expectations). No problem, he says. “We can do that in one afternoon.”

So he gets me to lie on the sofa, and we do the breathing. And yeah, I am a little bit in awe of my body, that I can hold my breath for two and a half minutes. And afterwards, as I said, I feel lightheaded, but also strong. Before the ice bath, he asks how many press-ups I think I can do. I dunno, maybe three, it’s been a while. He gets me to take 20 more deep breaths, and then, holding the final one, I do 20 press-ups!

“I love results, this is a result! See how strong!” he shouts. Zina barks.

Now for the ice bath. He goes in first, lowers himself in without a wince or a whimper, up to his neck, he looks as if he belongs. He does this every year on his birthday, taking a minute for every year. He’s got 63 coming up. This time he’s in for about five minutes, while Judith, the photographer, snaps away. No hurry, Hof knows it’s a good picture. Zina licks his nose.

Now my turn, here goes … Jesus! I feel the air rushing from my lungs and body tightening up, recoiling, saying: “What the actual …” But I am actually in.

“Relax, big breath, who’s in control?” says Hof. “Let the body do what the body is able to do, you are so much stronger than you think, you are going to be happy, the cold is real, it’s a force, your inner power, also your neurological networks, hormones, it all works for you, let it awaken …”

Not now, Wim, can I get out please? I was thinking maybe a second for every year of my life, so a little under a minute in total … He keeps me in for 90, after which I stagger out and straight into the sauna.

But I do feel good – invigorated and alive. He says I’ve done well, gives me fist bump. “We are strong, happy and healthy,” he says. “Children of mother nature. But also dads and we lead by example, not just money in society but feeling a million bucks every day.”

All very well, when you’ve actually got a million bucks. Twelve years ago, he was earning €7 (£5.85) an hour as a truck driver. “Now, for a keynote – which I’m not even doing any more – they give me 50,000.” How rich is Hof? How many million? “I don’t know, maybe 10,” he giggles.

I’ve thoroughly enjoyed my afternoon with the Iceman. Yes, he bangs on a bit, but that’s because he does passionately believe it. He’s also entertaining and funny. And extraordinary. He sat in an ice bath for one hour, 52 minutes and 42 seconds! It makes me hyperventilate just thinking about it.

Am I sold? Like I said, I feel great. I’m going to try the cold showers. Maybe a bit of breathing, too. The osteoarthritis, though, plus the odd visit from the old black dog … Well, we’ll see. But I’m not holding my breath.