Leonard Ortiz/MediaNews Group/Orange County Register/Getty Travis Barker
Health and wellness has always been a priority for Travis Barker.
"Our friendship and our relationship was started 10 years ago and I think we were both really into wellness," Barker says. "We were both really into eating healthy, working out, and being great parents."
Barker is dad to son Landon, 18, daughter Alabama, 16, and stepdaughter Atiana, 23. His blended family with Kardashian also includes her children — daughter Penelope, 10, and sons Mason, 12, and Reign, 7.
The couple stays fit whether they are at home or on the road.
Video: Fans praise Kourtney Kardashian for showing off her "real body" on Instagram
"We have matcha in bed every morning, no matter where we're at, we're at a hotel, we're traveling," he tells PEOPLE. "We work out. We walk or run three miles a day."
They also watch what they eat — or don't eat: Barker has been a vegetarian since he was 13. "I've been vegan for 16 years," he explains. "[Kourtney's] 99% vegan, which I love. There's no fur. There's no meat. There's no fish. My baby just needs to give up cheese, pretty much, and butter," he says jokingly.
Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories.
Steve Jennings/WireImage Travis Barker
He says that functional fitness is a big part of his routine when it comes to staying in shape. "I have a show coming up, so I'll do a lot of functional training. I'll run. I'll do a lot of battle ropes," he explains. "I want to be in shape, but it's also like, how can I play drums better? How can I not get tired? How can I be strong for my kids? How can I be better at Muay Thai? I think of all those things. And I just try to have my workout routine support all those things."
A long-term goal? "I would love to do a marathon one day," he tells PEOPLE.
But fitness is just one component of his holistic approach to wellness.
"Wellness means to me... I think there's millions of people around the world that think you don't have to pay for what you eat or how you neglect your body and how you neglect your health," he explains. "And I feel like at some point you got to pay up, and wellness has always been that for me.
"But I think you can get all the surgeries you want to look a certain way. You've got to pay your debt at some point," he continues. "I've always told my kids, just be healthy, drink water, don't use products that are toxic. I don't know. Just try to steer them in the right direction as much as I can."
The musician has been prioritizing his health even more recently after he was hospitalized for "life-threatening" pancreatitis this summer.
On June 28, Barker found himself in a life-and-death situation when he was hospitalized due to pancreatitis, an inflammation of the organ that aids in digestion and regulates blood sugar.
He has since updated his Instagram followers that he is doing "much better," and was photographed last month walking outside his recording studio in Calabasas, California.
"Oh what a scary and emotional week it has been," she wrote on Instagram in July. "Our health is everything and sometimes we take for granted how quickly it can change."