Kate Middleton Reveals the Fitness Routine That Has Prince William Telling Her She's 'Crazy'

The Princess of Wales said she "absolutely loves" this healthy habit...even if her husband doesn't!

Kate Middleton isn't giving a popular fitness trend the cold shoulder.

The Princess of Wales, 41, revealed that cold swimming is part of her fitness routine — even though Prince William, 41, is not a fan!

The couple appeared together with Princess Anne on an episode of The Good, The Bad & The Rugby podcast (hosted by Anne's son-in-law, Mike Tindall!) last month as the Rugby World Cup kicked off in France. Prince William, Princess Kate and Princess Anne are the patrons of the Welsh Rugby Union, Rugby Football Union (of England) and Scottish Rugby Union, respectively.

Princess Kate spoke about the importance of being active, something she's been encouraged to do since her childhood.

Revealing one of her current fitness hobbies, the Princess of Wales shared that she's into cold swimming.

"The colder, the better. I absolutely love it," she said. "Slightly to the point where William's like, 'Catherine, you're crazy.' And it's dark, and it's raining."

Related: Kate Middleton Shares the Creative Way She Tries to 'Squeeze in Exercise' Before Kids Go to School

While meeting well-wishers in Wales earlier this year, Kate shared that she even had a robe for after her swims, a remark prompted by someone who was wearing a robe to keep warm in the rain.

"She said she wears one of them when she goes cold water swimming," local mom Alison Cheeke told PEOPLE.

According to an article published by Harvard Public Health, cold water swimming is believed to provide mental health benefits in addition to physical exercise (although evidence is mixed).

Kate's sister, Pippa, is also a swimmer. She wrote about swimming being one of her go-to workouts while pregnant.

Mike also has some experience with cold swimming but for different reasons. He kicked off 2023 by participating in a polar plunge for Doddie Aid, an annual challenge encouraging physical activity to fundraise for research for a cure for Motor Neuron Disease (MND). Doddie Aid is organized by the My Name'5 Doddie Foundation, established by Scottish rugby player Doddie Weir, who died in November 2022 after being diagnosed with MND.

Kate also stays in shape by playing tennis (the couple's Anmer Hall home has a court!) and jumping on the trampoline with her three children before school.

The podcast also touched on Princess Kate's competitive side.

"I'm not going to say you're uber competitive," Mike said before pausing to give a nod indicating that she really was.

She replied coyly, "I'm not competitive at all."

"I've seen her play beer pong!" Mike said.

Related: Queen of Athletic Wear! See All of Kate Middleton's Best Sporty Styles Through the Years

When Mike asked if any of their competitiveness had passed down to their children — Prince George, 10, Princess Charlotte, 8, and Prince Louis, 5 — the Princess Royal, 73, interjected: “Just a little bit, I would suggest.”

“What I think is really interesting is that they are all obviously very different temperaments,” Kate answered, adding that “they are growing and trying out different sports.”

“They're obviously still really young,” she continued. “It's going to be interesting to see how that grows and develops."

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Princess Kate and Prince William are known to get competitive with each other during royal outings, from going head-to-head in a spin bike race (Kate won!) to facing off in a sailing contest (William came out on top!).

When it comes to table tennis, Princess Kate said that she and her husband have never "actually managed to finish a game."

"It becomes a mental challenge between the two of us," she said.

Prince William added that it comes down to “who can out-mental each other.”

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